I have a Paxton 1200sl (throwback from brenspeed) just recently had them install some Detroit rockers and 4.10 gears) waiting on the Barton short throw shifter to come in. But what a difference the gears made going for 3.31s (5spd Manual) to 4.10s. Also the cams opened it up as well and the exhaust is a little louder. I have an axel back and aftermarket H pipe and high flow cats. I think the next mod will be kooks headers.
As far as going to a smaller pulley you can but you would need a new tune and probably want to add an intercooler if you
Don’t have one already (assuming you have the 1200 not 2200).
I had mine dyno-ed back when the supercharger was installed and it was all stock but axle back (even stock mid pipe and cats) with 3.31 gears. It was a hot summer day and it put down 430ish if I renewer correctly. I’ll find the video and post it up. With the cams it should be around 450rwhp or so. Still on stock pulley (9-10Ibs peak)
Honestly plenty of power (mines a vert) and doesn’t take long at all to get up and going. I don’t race it or track it. Just a fun weekend cruiser. Next I will look at headers and probably intercooler and go to a smaller pulley. That’s about max you can go before getting into to much power / torque for the bottom end.