In my opinion, it would be absolutely worthless to swap out a c1 for a c5. The money would be much better spent on a turbo for the c1 motor. It depends on the kit, but a good turbo set up could run anywhere from $2000 to $6000. Talk to Westcoaststyle, as he has turboed his c1 pretty nicely. I think that most people on this board will also agree that a turboed b18c1 is much better than a b18c5:thumbup: