Reply to "aluminum flywheel"

Besides what Goran says, be aware that all alloy flywheels that I've seen have much thicker flywheel flanges where they bolt onto the crankshaft, due to the lower tensile strength of aluminum. So the working face of the clutch is moved back towards the transaxle significantly. This means a complete readjustment of your clutch linkage- probably including shifting the bellcrank on the splined cross-shaft a couple of splines. On some cars, the bellcrank end will touch the bellhousing when this is done, so some grinding on the bellhousing might be necessary. If the flywheel flange is thick enough, you may also need longer flywheel bolts.... and flywheel bolts are made with special short heads. This sometimes isn't quite a bolt-on mod!