ORIGINAL: Birdieman4

A few points. (You guys knew I was gonna chime in at some point, my kinda discussion) If you had to do a centrifugal, I do think the Paxton is best for performance. The bottom line, for me, on centrifugal blowers is that if I was running 9 psi I would buy an aftermarket intercooler. I would not run a centrifugal w/o in intercooler. Period. It makes the Procharger product look pretty attractive, as the intercooler is included in their kit. BTW, Procharger has had zero problems over the last year and a half, yeah, 2 years ago there were seal issues. Those have all been resolved, and Procharger kits, IMO, are MORE reliable than Vortech kits at this time. Look at the people who tell you don't go Procharger. Guys, the seal issue has been resolved for a while now! Those are typically people with Vortechs or Paxtons. On that note, the people who tell you to not go twin screw and go centrifugal are typically people who run centrifugal blowers. These are also people who haven't experienced twin screw blowers firsthand. When I comment on blowers it is with firsthand experience in centrifugal and twin screw units. I have owned and tuned both. Both provide advantages and disadvantages. The bottom line here is that twin screw blowers provide more advantages and less disadvantages over centrifugal units. -Especially on the street. If you were building an all out race mustang for use mostly at the track, a centrifugal blower would make a lot of sense. I'm not saying that a centrifugal blower doesn't make sense on the street, I'm saying a twin screw makes MORE sense. Maybe I should regurgitate the thread where MD said he would have gone with a twin screw if he had the chance at that point and time.

if i swap the pully for like a 9 pound pulley on the series 1 will i absolutly need to get a tuner or is there a chip or a reflash that will make all the timing/fuel adjustments for me?

No, the bottom line is, that if you have 2 cars that are identical, except one is running a KB and one is running a centrifugal, the KB car is behind the centrifugal car at the end of the race.