I belive A1s are competive.one thing about the counter flow head is its identical ports to the 1.8s, there turned 180, but I dont think it helps. mechanical lifters In my opinion will give you more lift with the same cam profile. the A2-3s do have 10.0:1 comp, and we have 8.5:1, thats the biggest down fall of the itb A1....but the A1 is 200-300lbs lighter? I just built an 84 gti ITB car so I have lots and lots of optamisim......

that is my 2 cents
Lael