The only VTEC head is the one off a B18C1 (GS-R) and it has a smaller combustion chamber so that will raise compression. The B18C5 or Type R motor uses a modified (supposvely some porting) B16A head. I would recommend you either replace the seals or get another B16A head. If you want to lower compression, I would suggest new pistons. More expensive than anything else, but definately money well spent on a turbo application.