Hey I was wondering about this. I know that doing work to the heads really does make a difference in performance. I was going to do some head work on the GS3 but didn't find anyone that could work on our cars. I was wondering if anyone has ported and polished heads on their GS3 or GS4XX?

Also, if so what does your performance gains look like. It can be the butt dyno, that's fine with me. I know that doing work to the heads is costly, but the gains that can be achieved make a big difference.

 

i had mine ported and polished, also upgraded the valvetrain completely. however i did it all while swapping the motor and turboing it, so i have no idea what/if any gains were had from that work.