Apparently they don't fit stock turbos and some of the larger gt30 frame turbos are a little tight as well. Ash's solution on the gt30's has been to double stack turbine gaskets thus far... I have been following closely as I was very interested in swapping my new set of MSP's for them but so far have not been impressed. I am surprised that this info hasn't been more widely circulated in the community since they have been available for a bit.