Come to think of it Karl, when we did the logs on yours there was no slip at all. I've been in Dans' car when his clutch was on it's way out and doing logs it used to slip like mad!
First car i've sat in with the B5 TIP and got to admit it sounds awesome and although MAF readings were the same as last time, the car did feel alot smoother and at ease. Like you say, i think you've maxed out the G/S for the standard boost/map
You'll have to try my ECU