Yep i can verify that a A12 flywheel WILL work and fit on an A15 as this is extacly what ive done. My A15 ring gear was shagged so just took the A12 flywheel to the dude and he said yeah they all fit and did a lovley lighting job for me.

And yeah it is MUCH thicker i reckon, like real fat around the middle of the wheel and much deeper aswell. If you notice (if you have one) on the A12 flywheel it doesnt have the huge lumps just below the ring gear as the A15 one does, thus making it lighter...

If my memory serves me right, when i weighed my stock A15 flywheel was about 9.8 - 10.2kg (i think) and my A12 one was about 8.7 - 9.1kg ?? does this sound right? But its now 5.2 kg so bit of a difference

Verification on that, over??

Dave