its all a matter of how much money you want to put into your engine mods, in this field, the sky is the limit, there are supercharger kits for 1uzfe out there, there are intakes, exhaust kits etc, but i agree with nc211, why?
LS engine is very undertuned i agree, this is what gives it its reliability since it is not exposed to the stresses of the sport engine, you can squeeze up to 800 hp on this block without doing very extended modifications, as one person in australia did when he installed 1uzfe in the supra, but in the LS case, engine is restricted by the transmission, which is also programmed for the smooth ride, exhaust, intake and of course ECU. what chips usually do, is they are being attached to MAF sensor and then send modified signals to ECU to trick it into sending richer mixture into cylinders. this means your fuel economy is going to suffer and different components of the engine are going to be but under extra stress, ask yourself again, do you really want it? there are bunch of other car models out there that are a much better fit for modifications. (E.G. civics, thats why i got one:) )