Does anyone know the true reason why TPC's supercharger has problems?

[HB.]

Guys, thanks for chiming in, but I was really seeking the real facts as to why they have had problems. I believe Insite's reason for how the blower is mounted is one major issue.

Lux
No they are not inter/after cooled, but they do use a srew-type blower that conducts it's own compression vs. the roots type that just moves air. Both, the NSX and Boxster are virtually running the same compression ratio. Heatsoak would also be a good factor for any related failures. Both cars have very tight engine compartments, so I'm just wondering why it works for the NSX and not the Boxster? Better engine maybe???

Brucelee
There are plenty of 996 onwers who are running centrifugal superchargers, and have had no problems thus far. Does the 996 use different engine internals then the 986? If you can run a centrifugal blower that spins almost twice as fast as a PD blower and not have problems, why can't these motors handle less boost, less CFM?