GSX with a JDM i believe 4G63 or 4G63T engine. I was wondering if i should keep my dsm Unorthodox Underdrive Racing pulley system with adjustable timing sprockets on of go back to the OEM ones?

ok, lets start with there is no JDM anything about your eclipse. it was made in Normal, Illinois and any that are in Japan were shipped there. now your engine, its a 4g63, the T part just means turbo. so if you got a turbo then feel free to put the T on the end, but its most commonly refered to as a 4g63 by everyone. as for the pulley, its not gonna hurt any to have it on there. just dont go messing with the thing, only wind up screwing your motor to hell if you dont know what your doing.

Alright also, I was thinking about putting the FP T-28 turbo on it since it's a direct bolt on. Now as far as I know this will put me into the 300-350whp. With supporting mods. Would buying the t28 be a good choice or would it be better for me to buy the evo big 16g turbo?

Because the engine is the evo 4G63 the options for bolt on turbos are abundant. if you do choose to go excessively larga than the adjustable cam gears will come in handy with a decent dyno tuner to extract the max output and responce from the engine. the underdrive system, if you are not seeing any battery charge, pwr steer or overheat issues, will only make the dyno numbers more impressive. just remember also that the linked ancilleries will also need an upgrade if the turbo is to be increased, especially both sides of the cooling system.

Ok so then which one would be best choice for a upgraded turbo? The FP t-28 or the big evo 16g. Or are there any other sub $1000.00 turbos that are reliable and better than those two?

turbo reliability on a brand name unit generaly comes down to maintainence and common sense. other than the factory units you mentioned have you comsidered the likes of a Tomei M7960 ARMS turbo, bolt on kit for slightly over your $1k budget, or perhaps a Typhoon Series T72 turbo by Godspeed. Decent price, new unit and warrantable.