There are pros and cons for both, but you already have the PC and it is a competent tuner, so I would definitely keep it. If you had SEPST I would probably say the same thing. Find a good map for it and ride.

 

If I bought a used bike and it already had a tuner on it, I'd learn to use that tuner. Remember this, it's the tuner (person), whether that is yourself or someone else, that get's the performance where you want it moreso than the tuner (equipment). As long as the tuner on the bike has the features and capabilities you need - keep it.

 

I had a S.E.R.T installed so far so good but its to soon to tell,got good numbers from the tuner on the dyno.IMO