The difference between the 1k and 2k besides the output capabilities are the flow #'s of each. I can't quote and #'s off the top of my head but the 2k flows ALOT more air than the 1k. For a street car, the 2k would probably be overkill unless you plan on running more than 15 psi.
Alot of people use the F150 crank pulley because you can get one for ~$20 and it will give you 2-3 psi. That's cheap power. Paxton recently revised the 1k though. It used to be a single belt design (one belt drives the blower and accessories) and now it's a two belt design. With the switch, the F150 can no longer be used. It only works for the 'old style' single belt design.
The FMU is junk. It's just a band-aid for your fuel system and allows you to put the blower on without going with bigger injectors or fuel pump. IMO, the car will be easier to tune WITHOUT the FMU. Just get a set of 30# injectors and a bigger fuel pump and scrap the FMU.
If you can find a used 'old style' 1k (with the single belt) you could pick that up and throw on a F150 crank pulley. With that setup, you'll see 8-9 psi. Also, regardless if you get the old style or new style 1k, you're going to benefit from a bypass valve. The NOVI's seem to run smoother with a bypass valve. The part # can be found somewhere on
www.novipower.com and runs about $30. With your stock motor, 8-9 psi should be fine without any worry.