i was looking at tunes from KT Performance

intake and exhaust are more supporting mods like someone said. I wouldn't be surprised if you told me you put them on and lost power on the dyno just as much as you gained only a little.

As far as your mods to your 300C, unless you did back to back dyno runs right after the install, on the same day, I don't believe that either. Especially without adding a tune to it for the intake/exhaust.

I watched a low 500rwhp duramax dyno one day. Did 3 pulls, shut truck off, put a well known intake on the truck, re-ran the dyno right then (truck never came off the dyno) and the numbers were exactly the same. Not a single change. You'd think a truck making over 500 at the wheels would be choking for air on the stock setup eh?

if you read my edit, i was running custom diablosport predator tunes, not just the canned crom files, thats probably why i gained as much as i did, and yes it was dyno'd same day same location before and after

Ahh didn't see it, with the mods AND the programmer, I could see that. That's key, tuning the vehicle to match the mods.