I heard from a VERY reputable source that the problem with using small port precups on a turbo motor is that the cup will get excessively hot and you will get rapid erosion of the port. I wonder what material the precups are made of. They are simply called "stainless steel", but that covers a wide range of alloys, none of which are the best for a precup IMO. HD IDI's usually use a Nimonic alloy (similar to Inconel)... is that what the cups in the 6.x are that are reffered to "stainless steel", or is it some cheaper alloy...?