Stay away from the street tuner.....its pretty mcuh for the dealer to download a canned map. You cant do anything with it yourself.
SEPST (Pro tuner) has SmartTune and you can do your own tune
TTS has VTune and you can do your own tune, and has more variables you can adjust over a SEPST
SEPST and TTS are both great products that many professional dyno tuners can tune your bike with. Obviously, with only pipe change you dont need much, so either SEPST or TTS is a good choice.
I would ask your tuner what he/she prefers to use. And, go with that. Since TTS is the old HD Race Tuner product brought into the modern age, any veteran pro tuner can tune the bike with it. So, that may sway your decision. Neither one will void your warranty, dont let anyone BS you any different.
Dennis