PG has always made some nice equipment. I haven't tried any of their fairly new stuff, but I used to have a XS4600, sounded good, was powerful, and bulletproof. I've heard good things about the titanium series of amps. I believe they are based on the older ZX series amps?

 

SUX2BU, The MPS where the low impedance amps (1 ohm), MS was the standard 4 ohm typ.

LemonLime, Are you refering to the orignal white ZX amps? OR the ZXti?? The older white series while they look similar to the ZXTi and Titanum they are very different inside and where pretty much redisgned.. Now the Previous ZXti and the current Ti amps are exactly the same inside, just a different name.