IMO, the SERT is better. Plus it doesn't have to stay on the bike like the PCIII

 

Ok, so I talked to the previous owner just now and he said he can get the dongle but no cables. Where can I get cables or do I need them? If I get the cables can I tune it from my own pc? DO I need software?

 

You can buy the cables from HD. You would need a disc with the software on it, but you can also copy it from an online source (in fact I think someone posted the link here somewhere recently) You can then choose a canned map from the software and load it by hooking it up to your pc or laptop. Optimally, you should get the bike tuned on a dyno.

 

If you get the SERT, you can take it to a tuner and have your bike dyno tuned, you won't need the cables of the program and you won't have to put in a "canned" MAP and hope it's the right one for your bike.