peak HP vs average HP ? And at what price? When a 460 horse LS2 only gains 10 horses by switching from 1.75" to 1.875" primaries, and I'm not sure your combo is there even with spray, ( though I'm sure you at least hope it is ), then maybe you're not ready yet. In which case, you can be watchful for a really good deal, rather than spending a lot more just to have them right now. Because at present, swapping up might find you a few more peak HP, at the top of the tach, when using the spray, but your average power surely would suffer. Even with a re-tune.