Most of those "Chips" are ****, unless they are a full replacement daughter board with programmable eeprom on them, your probably looking at a poor return on $$$.
If your chasing more power, do more modifications (camshafts, compression, intake, extractors, exhaust) and then move to an aftermarket computer to be able to take full gain of all modifications. Trying to run sizable modifications on the stock ecu generally ends in problems.
An exhaust upgrade probably won't net any significant gains to worry about spending the money, the stock ecu should be able to handle the slight changes within its range of adjustments.