Hi Having tried unsuccessfully to get my factory rear speakers and sub to work with autoleads adapters, I've finally decided to replace the existing amp and sub. I would like an amp that powers a single sub and also the rear speakers but will let the new pioneer head unit power the fronts. I want something that doesn't take much space so I guess my options are: Replace the factory sub with a free air sub or Fit an enclosed sub in the boot cubby hole I've seen sub boxes fitted into the rear left cubby hole (think AndyMac has done this with a 6.5" sub) but can't find any enclosures small enough to fit (and don't want to have to build one myself). If I could find a half decent sub-amp package that would fit that would be ideal. Anyone able to suggest anything? Also, just to check, in order to run a sub and rear speakers do I need a 3 or 4 channel amp?