Couple more tips...

Anything that is steel that can be replaced with aluminum, do it. Rear sub frame, front fairing/instrument stay, clip ons, etc...

My race bike doesn't have an airbox. It runs wide open carbs, but you need to think about this when jetting.

Also, figure out how much gas your bike will need to run the distance it needs to go, and put just a little more in it. Don't fill your tank to the top if your only running an eight lap spring race. Fluids can add a huge amount of weight to a bike.

Change the rear sprocket from steel, to aluminum.

Chain - Good quality race chain. They are expensive, but they are also mostly designed for bike heavy bikes. They will last much longer on a small 250.

Body work - Get ride of the stock plastic stuff, and go with a light weight fiber glass set. Not to knock TYGA, but their stuff isn't race quality stuff (unless they have changed it in the past year). They built their body work for street use, and it's a little heavier to keep up longer. Get Airtech, or if your in Japan, try Coren. My Coren body work is less the half the weight of my TYGA body work.

Exhaust - Again, get an aftermarket setup. TYGA, Jha, i-Factory, DogFight, etc... anything is better then stock, and the weight savings are HUGE.

Suspension - You don't need to swap it out, but get it rebuilt, resprung, and revalved for racing. This is the first thing I do on any bike I put on the track! I currently have a 2001 Honda RS 250 full front end all ready to bolt onto my MC28. I have put three weekends on the MC28 after it's been setup for me (suspension wise), and I have decided to hold off on the swap. The bike is feeling just fine as it is with the stock suspension.

Brakes - These things are over engineered for the NSR! You dont need to worry about them. Stainless steel lines, bleed them out, put good pads on the bike, and keep the pistons int he calipers clean. They will put the bike on it's nose from 120! Trust me, I came into turn seven last weekend skidding the front tire, with the rear in the air!

Engine - a good porting on the cases, and barrels is only worth more power. It can be expensive to do, and not many know these bikes to do it properly. Find a good place to do the work. A nice light weight flywheel is well worth the money. TYGA has then for sale. Anything that spins that can be lightened get it!

I am sure there is more, but this is getting pretty long. Oh, on the subject of an Aprilia RS getting even close to 100HP. Aint going to happen! That is unless your talking about a factory works bike. People struggle for the same 75 HP on the Aprilia that we struggle for on the NSR. The TZR can be made to do it easly, as the TZR shares parts with the TZ. You can just swap parts in to get more power on that engine. The newer RVG's can be made to go quick, but they crash all the time, so no one really knows if they can finish a race :)

Thanks,
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Charles Gallant