I used to run HKS 264 Step 1 cams with the stock T25. The cams will change the powerband a little with the turbo. Stock cams and T25, its like instant power as soon as boost is touched. With the 264 cams, you will have your boost then the power will kick in hardest around 4krpm. From when i had them and the T25, i say there was a gain of about 10-15tq around 4krpm but would still drop off at higher rpm cause the turbo is too small. Currently im running 270 cams with the 2871R .86 turbo. It has a similar feel to it. Boost hits 18psi around 4400rpm but the power doesnt hit hardest till 5krpm. As long as rpm's are above 3500rpm the setup is very responsive. Its one of those feelings you need to drive the car to understand.