Kando dynamic do quality line kits for about $100. I would NOT call them ebay crap. Have used them myself in the past.
As for your setup, aslong as you have a decent gate (tial mvr or similar) and you replace that cat, you will be cool. A decent 3" cat is only $189, why skimp?
Also you did not mention an FMIC, make sure you have one of these too.