im looking to get an aprilia rs 125, but am wondering why the name of the bike in some cases has got an R(aprilia rs 125R??) on the end or got something like extrema or futura next to it. are these versions of the aprilia rs 125 more powerful or better in some way, or is it plainly just a name. but why put a letter r on the end?? someone help, im just a novice and aint got a clue about bikes!!!!