I have not spoken to Bill directly about the s-84 being discontinued but when I called and spoke to Joe about the chip for The 95 K2500 GMC we discussed the the p-38 and I mentioned my disappointment in the s-84 being no longer available. I gathered that they felt without a wastegate on a stock truck with no mods from a simple replacement turbo perspective that the average joe would not be happy with response on the s-84. I guess it would be like putting a big cam in a gasser with no gear, no stall, no headers, and a small carb. Ditto on the top end loss not being noticed... I believe the way it was put to me in most normal driving situations there is no difference in power between the turbos.