The M90 is too big unless you go with a very well ported 16v head, 02A transaxle and wide sticky tires.
The M62 is what GM uses on the Cobalt. (Big pulley, 3"+ IIRC)
The M45 is good for ~200 to 220Hp at the crank. Most of us with the Neuspeed kit are running around 170 to 180Hp at the crank. The trick to getting more is an intercooler.
An M45 will probably be difficult to find but Bill'* suggestion of an M62 should work.
With a little head work and a good cam (Techtonics 260/26
it should be good for over 200Hp at the wheels.
Most people who have done this mount the blower in front of the engine. BBM does this with their Lysholm kit.
I see you have already tried the vortex. Search for "Eaton" in forced induction, archived content
; there are allot of posts some may be useful.
What are you using for engine management and fueling?
Welcome to the club, you will find it very different from the vortex.