Chips don't do much unless they're tailored for the actual mods you have on the car. The stock ECU as it stands is not really a limiting factor in making power. Unless the car has a lot of internal mods it is not going to really benefit from any changes to the stock ECU *unless* it is tuned on a dyno.

So...I'd get a shifter. Neuspeed and skunk2 both make nice ones.