Peformance wise, they helped a little bit. I think once you get into a bigger turbo, of start getting into increased flow (uppipe, tb exhaust, etc), you will start to notice it a little more. The biggest thing I notice, is that it lowered my intake temps about 15-20 degrees before the intercooler (I have an temp probe installed in the elbow going into the intercooler). From what I have been reading, trying to keep the incoming air cold is going to give the biggest gain. To me, it wasn't a seat of the pants improvement, but it is going to be a big puzzle piece once everything gets completed.