The V3 Si is the perfect blower, the compression isnt that much of a problem with 8-10lbs of pressure aka stock pulleys if the tune is good intercooled or not. If it me a is something you are concerned about you can just use a thicker head gasket but I wouldnt sweat it. I would just use the factory
Vortech upper and lower pulley combo and have the tuner creep up on timing especially under peak rpms since most guys tune for WOT and dont play with 1/2-3/4 throttle bursts or acceleration areas and thats usually were a street guy will run into issues unless they ride the rev limiter too much first. If you decide to go
Vortech let me know I get pretty good hookup with them
either way good luck and have fun!