diff --git a/swing/src/net/sf/openrocket/gui/adaptors/DoubleModel.java b/swing/src/net/sf/openrocket/gui/adaptors/DoubleModel.java
index d7c58e352..fa73b044f 100644
--- a/swing/src/net/sf/openrocket/gui/adaptors/DoubleModel.java
+++ b/swing/src/net/sf/openrocket/gui/adaptors/DoubleModel.java
@@ -580,7 +580,7 @@ public class DoubleModel implements StateChangeListener, ChangeSource, Invalidat
 	
 	private final ArrayList<EventListener> listeners = new ArrayList<EventListener>();
 	
-	private final UnitGroup units;
+	private UnitGroup units;
 	private Unit currentUnit;
 	
 	private final double minValue;
@@ -877,6 +877,13 @@ public class DoubleModel implements StateChangeListener, ChangeSource, Invalidat
 		currentUnit = u;
 		fireStateChanged();
 	}
+
+	public void setUnitGroup(UnitGroup unitGroup) {
+		this.units = unitGroup;
+		this.currentUnit = units.getDefaultUnit();
+		this.lastValue = this.currentUnit.toUnit(this.lastValue);
+		fireStateChanged();
+	}
 	
 	
 	/**
diff --git a/swing/src/net/sf/openrocket/gui/dialogs/optimization/GeneralOptimizationDialog.java b/swing/src/net/sf/openrocket/gui/dialogs/optimization/GeneralOptimizationDialog.java
index e28bf0ad9..59ce8c45a 100644
--- a/swing/src/net/sf/openrocket/gui/dialogs/optimization/GeneralOptimizationDialog.java
+++ b/swing/src/net/sf/openrocket/gui/dialogs/optimization/GeneralOptimizationDialog.java
@@ -380,6 +380,12 @@ public class GeneralOptimizationDialog extends JDialog {
 		optimizationParameterCombo.setToolTipText(tip);
 		populateParameters();
 		optimizationParameterCombo.addActionListener(clearHistoryActionListener);
+		optimizationParameterCombo.addActionListener(new ActionListener() {
+			@Override
+			public void actionPerformed(ActionEvent e) {
+				updateSeekValueUnits();
+			}
+		});
 		disableComponents.add(optimizationParameterCombo);
 		sub.add(optimizationParameterCombo, "growx, wrap unrel");
 		
@@ -404,7 +410,7 @@ public class GeneralOptimizationDialog extends JDialog {
 		optimizationGoalSpinner = new JSpinner(optimizationSeekValue.getSpinnerModel());
 		tip = trans.get("lbl.optimizeGoalValue.ttip");
 		optimizationGoalSpinner.setToolTipText(tip);
-		optimizationGoalSpinner.setEditor(new SpinnerEditor(optimizationGoalSpinner));
+		optimizationGoalSpinner.setEditor(new SpinnerEditor(optimizationGoalSpinner, 4));
 		disableComponents.add(optimizationGoalSpinner);
 		sub.add(optimizationGoalSpinner, "width 30lp");
 		
@@ -554,6 +560,7 @@ public class GeneralOptimizationDialog extends JDialog {
 					Collections.unmodifiableMap(evaluationHistory),
 					Collections.unmodifiableList(selectedModifiers),
 					getSelectedParameter(),
+					optimizationGoalUnitSelector.getSelectedUnit(),
 					UnitGroup.stabilityUnits(getSelectedSimulation().getRocket()),
 					GeneralOptimizationDialog.this);
 			dialog.setVisible(true);
@@ -606,6 +613,7 @@ public class GeneralOptimizationDialog extends JDialog {
 		this.add(new JScrollPane(panel));
 		clearHistory();
 		updateComponents();
+		updateSeekValueUnits();
 		GUIUtil.setDisposableDialogOptions(this, null);
 
 		int screenHeight = Toolkit.getDefaultToolkit().getScreenSize().height;
@@ -834,13 +842,22 @@ public class GeneralOptimizationDialog extends JDialog {
 		evaluationHistory.clear();
 		optimizationPath.clear();
 		bestValue = Double.NaN;
-		bestValueUnit = getSelectedParameter().getUnitGroup().getDefaultUnit();
+		bestValueUnit = optimizationGoalUnitSelector.getSelectedUnit();
 		stepCount = 0;
 		evaluationCount = 0;
 		stepSize = 0.5;
 		updateCounters();
 		updateComponents();
 	}
+
+	private void updateSeekValueUnits() {
+		if (optimizationSeekValue != null && optimizationGoalUnitSelector != null) {
+			optimizationSeekValue.setUnitGroup(getSelectedParameter().getUnitGroup());
+			optimizationSeekValue.setValue(0);
+			optimizationGoalUnitSelector.setModel(optimizationSeekValue);
+			optimizationGoalUnitSelector.revalidate();
+		}
+	}
 	
 	private void applyDesign() {
 		// TODO: MEDIUM: Apply also potential changes to simulations
@@ -1168,7 +1185,7 @@ public class GeneralOptimizationDialog extends JDialog {
 					writer.write(fieldSeparator);
 				}
 				writer.write(getSelectedParameter().getName() + " / " +
-						getSelectedParameter().getUnitGroup().getDefaultUnit().getUnit());
+						optimizationGoalUnitSelector.getSelectedUnit().getUnit());
 				
 				writer.write("\n");
 			}
@@ -1187,7 +1204,7 @@ public class GeneralOptimizationDialog extends JDialog {
 				}
 				
 				if (data.getParameterValue() != null) {
-					writer.write(TextUtil.doubleToString(data.getParameterValue().getUnitValue()));
+					writer.write(TextUtil.doubleToString(optimizationGoalUnitSelector.getSelectedUnit().toUnit(data.getParameterValue().getValue())));
 				} else {
 					writer.write("N/A");
 				}
diff --git a/swing/src/net/sf/openrocket/gui/dialogs/optimization/OptimizationPlotDialog.java b/swing/src/net/sf/openrocket/gui/dialogs/optimization/OptimizationPlotDialog.java
index 6dda9fa3e..d92438b2c 100644
--- a/swing/src/net/sf/openrocket/gui/dialogs/optimization/OptimizationPlotDialog.java
+++ b/swing/src/net/sf/openrocket/gui/dialogs/optimization/OptimizationPlotDialog.java
@@ -80,7 +80,7 @@ public class OptimizationPlotDialog extends JDialog {
 	
 	
 	public OptimizationPlotDialog(List<Point> path, Map<Point, FunctionEvaluationData> evaluations,
-			List<SimulationModifier> modifiers, OptimizableParameter parameter, UnitGroup stabilityUnit, Window parent) {
+			List<SimulationModifier> modifiers, OptimizableParameter parameter, Unit parameterUnit, UnitGroup stabilityUnit, Window parent) {
 		super(parent, trans.get("title"), ModalityType.APPLICATION_MODAL);
 		
 
@@ -88,9 +88,9 @@ public class OptimizationPlotDialog extends JDialog {
 		
 		ChartPanel chart;
 		if (modifiers.size() == 1) {
-			chart = create1DPlot(path, evaluations, modifiers, parameter, stabilityUnit);
+			chart = create1DPlot(path, evaluations, modifiers, parameter, parameterUnit, stabilityUnit);
 		} else if (modifiers.size() == 2) {
-			chart = create2DPlot(path, evaluations, modifiers, parameter, stabilityUnit);
+			chart = create2DPlot(path, evaluations, modifiers, parameter, parameterUnit, stabilityUnit);
 		} else {
 			throw new IllegalArgumentException("Invalid dimensionality, dim=" + modifiers.size());
 		}
@@ -134,11 +134,11 @@ public class OptimizationPlotDialog extends JDialog {
 	 * Create a 1D plot of the optimization path.
 	 */
 	private ChartPanel create1DPlot(List<Point> path, Map<Point, FunctionEvaluationData> evaluations,
-			List<SimulationModifier> modifiers, OptimizableParameter parameter, UnitGroup stabilityUnit) {
+			List<SimulationModifier> modifiers, OptimizableParameter parameter, Unit parameterUnit, UnitGroup stabilityUnit) {
 		
 		SimulationModifier modX = modifiers.get(0);
 		Unit xUnit = modX.getUnitGroup().getDefaultUnit();
-		Unit yUnit = parameter.getUnitGroup().getDefaultUnit();
+		Unit yUnit = parameterUnit;
 		
 		// Create the optimization path (with autosort)
 		XYSeries series = new XYSeries(trans.get("plot1d.series"), true, true);
@@ -232,10 +232,7 @@ public class OptimizationPlotDialog extends JDialog {
 	 * Create a 2D plot of the optimization path.
 	 */
 	private ChartPanel create2DPlot(List<Point> path, Map<Point, FunctionEvaluationData> evaluations,
-			List<SimulationModifier> modifiers, OptimizableParameter parameter, UnitGroup stabilityUnit) {
-		
-		Unit parameterUnit = parameter.getUnitGroup().getDefaultUnit();
-		
+			List<SimulationModifier> modifiers, OptimizableParameter parameter, Unit parameterUnit, UnitGroup stabilityUnit) {
 		SimulationModifier modX = modifiers.get(0);
 		SimulationModifier modY = modifiers.get(1);