I have an 03 Mitsubishi Evo VIII on my lift right now. It has a p0300 code(random misfire). You can feel a slight miss at idle. Anyway, I road tested it and watched the factory boost gauge. It read 1.5kg/cm2, that comes out to about 21.4psi.... thats almost 5 pounds more than it is suppossed to be pushing. I can't find ANY boost controller(manual or electrical), and I've been over the car over and over. I have a call to the customer to see what all he has done to the car. All I see is an aftermarket blow off valve, 3" downpipe, high flow cat, and a full 3" exhaust. It runs fine when you lay into it. The tailpipe and rear bumper are black though. Plugs didn't look rich however(one side was white/lean, other looked decently normal). So anyway, I can't see it being possible, but could a full 3" exhaust turbo-back cause a 5psi increase in boost?? Stock exhaust is something like 2 or 2.25 back to the cat then 2.5 out. I'm trying to avoid calling Mitsubishi technical hotline, because I don't want to screw this guys warranty. If I call and say he has the upgrades I see, hes screwed. And as someone who would like to own/mod one of these cars, I don't want to **** anyone over on one.