mileage usually isnt an issue with M90 superchargers...before i upgraded to my genV blower, i had 175K on my original. and it's had considerably smaller than stock pulleys on it since 100K..... i would just recommend getting a new coupler/oil while it's off the car. if you are going to top swap your L36, make sure you at least have a CAI and 3" downpipe...even with a stock pulley. the increased compression of the L36 makes it comparable to having a smaller supercharger pulley. this will help you to make more power however, because you can achieve the same cylinder pressures without spinning the blower as fast, so you have less parasitic loss....top swaps are the way to go

 

I agree. I wish I had 9.4:1 compression... Then you could still mill the heads and achieve higher compression. Then add boost? Sheeeeet.