Plunk,
The stock S-trim is pullied for 6-8psi. As far as centrifugals go, there isn't much in terms of an entry level blower for our 94-95GT/Cobra's. The only reason I went with Powerdyne was the price. A Ford Motorsport dealer offered it to me for $1800 brand new. I couldn't pass up the deal. I have been lucky though and have had some success with it. Another option is the non-intercooled P1SC from Procharger. It was about $400 more than the Pd I got but is a 1200cfm capable blower but I hear it can be a pain to install. As with all superchargers though, there is good and bad with every product. Just keep doing research on sites like the Corral and Stangnet. They have some really good info. Look under product review (power adders) on the Stangnet and there are reviews for just about every supercharger out there.
I was just curious about the Powerdyne since that has become the subject here and there were 24 post about the BD-11A, 19 good, 5 bad. I say 5 bad because that's how many had broken internal belts but a couple of them still liked the supercharger
I don't think I would be to happy with a failing blower. Anyway, again, good luck.