I took off my roush m90 with the 8 psi pulley and installed a paxton 2200 novi with the stock 10 psi pulley over Christmas.
Nothing else on the car was changed and the car was ran on the same dyno ( mustang dyno ) with the same guys tuning both superchargers and here is what I found.
First of course is the HP TQ. These are weather corrected numbers so it is truely apples to apples.
Roush m90 382.6 Hp @ 6201 rpm.............339.6 TQ @ 4688 rpm
Paxton.......440.6 HP @ 6194 rpm............380.6 TQ @ 5289 rpm
The paxton actually made more power across the board at all rpm above 2800 and very close from idle to 2800 rpm.
The roush felt a better burst at 2000rpm,
but only because it throws all 8 psi at that point so you get a cool surge, but that is just seat of the pants feel ,,
the dyno says there is no more power than the paxton.
The roush Got 16 to 17 mpg
The paxton has got me back to what it was stock 19 to 20 MPG
The paxton is quieter, but I did like the roush sound.
The Paxton is great because I control the boost I want by throttle and rpm, so if you do any road course track days the paxton is a much better choice.
Now for the Bad points of the paxton.
Roush looks much neater under the hood. ( you can change your belt without taking apart the SC) Paxton looks like a plumber's nightmare.
I think the Roush sounds better ( OMHO )
The roush instructions were MUCH better than the paxtons were.
The roush installed in one long day for me, the paxton 2 very long days.
the guys who tune the car both times were suprised the paxton did so much better, and my wife loves driving it again because it is so smoooooth now.
well there you have it.
As for me and my car???????
Well what can I say?
$2500 plus shipping and you can have my m90 complete.