Hi mate I've recently made a similar change I can't see me ever going back.
I had an 07 ZX6r that I spent over £4k getting it up to Superstock spec, but I got pissed off going every where at a million RPM doing 30mph, so I traded it at my mates shop for an 06 reg 05 Factory and love it to bits.
I took it to Brands on 7th of April two weeks after buying it and it is a F**king brilliant trackbike (although I have spent some time getting the basic setup how I like it) it was lapping within 2-3 seconds of my ZX. I'm the limiting factor on this bike.
the handling on Diablo Supercorsas is confidence inspiring enough for me to have pretty much scrubbed the whole front tyre
I can't advise on reliability as I've owned the bike for nearly a month but researched RSVRs prior to buying one and believe the engines to be bullet proof, Although the charging system can sometimes have issues which can lead to a flat battery and eventually a knackered Sprag clutch on the starter optimate is a wise precaution (there is a fix
http://www.apriliaforum.com/forums/showthread.php?t=171391&highlight=brown+connectors).
The clutch slave cylinder apparently needs regular bleeding as does the back brake I've never used mine so can't comment, alternative slave cylinders are available although I'm not going to bother as I don't mind the clutch pull although I may fit a better billet master cylinder.
I have found that neutral is a ***** to find and have just received a .04 clutch jet which I'll be fitting tomorrow which is supposed to cure that issue.
If you buy an 04-05 check to see that the swingarm recall has been carried out mine wasn't and Inmoto have me booked in on the 11 may to do that job not a big deal but a PITA.
Oh the side stand is **** I've fitted a 20mm nylon block under mine.
Beware of any CHEAP non STD levers they can cause the front brakes to bind or even come on due to insufficient free play on the brake plunger so stick to genuine or quality like Pazzos etc.
There was an update in 2006 a few detail changes like the rear seat unit, front fairing, smaller clutch oil jet, bigger valves etc and also I believe the offset of the forks was changed although I haven't been able to confirm that.
Go out now and buy one.:thumbup
PS I was advised that using the recommended grade of oil is a must 15/50 semi synthetic I also fitted the later oil filter housing and longer filter for no other reason than having bigger filter made sense to me and it only cost £20 for the upgrade.
