Yes it is a newbie question, but from what I have read it seems to be due to pressure changes in the exhaust...? Is it boost occuring at a later time (hight rpm)? or is it refering to pressure from the turbos?

 

Boost crep is when you floor it, the boost jumps to 10psi (or whatever your car is supposed to run) and slowly keeps creeping up. A friend of mine had a serious boost creep problem in his DSM. He would boost to 15 and it would keep climbing to about 22, very bad. His was a result of much freer flowing exhaust, and intake. You can combat boost creep with an electronic boost controller or a manual controller with a, umm, I forgot what the regulator in those is called. Boost creep is your enemy!

 

It is caused when the turbo output is too much for the wastegate to handle, and the extra air has no place to go but into the engine, causing more boost than you want. It would be similar to if you turned a water faucet on "high", and the drain hole in the sink were not large enough to handle the flow rate, which would cause the water to rise in the sink.

A fancy wastegate controller will not solve the boost creep problem. If you want to stop boost creep you either need to make the turbo flow less (you can usually do this with your right foot ), or make the wastegate flow more.