Just thought I'd give my opinion of all the work I've done to my xp & what I'd do differently if I was to do it again! Lets start with what I've done, I bought a used air-air kit that came with 9-1 cp pistons and lots of other parts, pretty good deal, then I decided lets do it right the first time & fire ringed the cylinder, cnc ported the head, valve springs, cams and arp head studs thinking this should rip & hold together! Well got it all together fired up running pig rich at idle can't lean it out any more so test drive time it's a dog out of the hole but pretty cool on boost , clutching issue so I get my clutching pretty good for 6k feet altitude seems pretty good just suprised at how much boost lag I've got! Then I went up camping @ 9k feet on the woods & it just seems like this thing is laboring unless on boost, so not much fun to drive! So long story short if I had to do it again I think I'd do a low boost kit or just not do all the internal eng work through a set of valve springs at it and keep the boost at ten or lower!