The biggest problem I have observed is that some Talon's steering rack (not the steering wheel) is not centered upon delivery and/or the toe is not set correctly. What I have seen many times is the rack is off center and the steering wheel is installed straight/wrong to compensate. This causes the machine to turn sharper in one direction. And if it is toed out, it makes matters worse. Not sure if that is a factory or dealer mistake but it is ultimately up to the dealer to get it right. My R was delivered toed out AND the rack off center turning much sharper to the left than the right but I have seen both ways.
They do build in a little tolerance/leeway in case the front geometry is off due to rack center, toe, bent parts, etc. but the front CV's on the Talon are only a few degrees away from binding so when the rack is off center and/or toed out, the CV on one side can be very close to its bind limit and adding forward swept A-Arms pushes it over it's limit. Thus by installing the stops, you put the CV angles where they were before installing the A-Arms and maintain the initial factory tolerance/leeway. Are the stops needed? Yes and no, depending on how good you are at maintaining (namely aligning) your machine.
That said, if your rack is perfectly centered, toe set to zero, the frame and suspension are not "bent" and everything is perfect, there is enough leeway left in CV angle to play with and the stops are not needed with the forward swept A-Arms. However, IF anything goes out of whack, you may bind the CV and/or see early CV failure.