Originally posted by Magik
I've been told that a d15 with the Si distributor and the Si MPFI can actually end up making more HP than the stock A6...is there any truth to that?
No.
Why exactly does your Si not have a D16A6?
If you swap the heads, you'll be fine. The only issue you'd run into would be needing a new head gasket, and new head bolts would be nice.