I`ve installed both, driven both, and seen both make big power. For a street car, auto, 450 rwhp I recommend a PD blower. For big power (700rwhp) a centri or turbo is the ticket. Go with Roush over the Paxton for this application.
07 GT vert, Satin Silver, 5spd, premium trim, interior upgrade pkg, comfort group, GT appearance package, cloth top
ADDED: 302 Stroker, KB 2.8 Mammoth @ 20psi, DOB belt drive, E85 fed, TR6060, ATI, Cervini hood, Meziere, Pypes Long Tubes, O/R X pipe, FRPP GTA mufflers, 20" Bullitts, Eibach Springs, BMR relo brackets/UCA/LCA`s, FRPP 4.10, etc, etc.