i read this one article from ninja250.org that makes your rpm go down for those people who have them....how is it and how much did it cost overall and is it easy to install if i decided to install it myself
What was the article about? Sprockets?
Seems like it'd have to be that, if it's changing rpm at highway speeds.
It's straight forward if your technically inclined, unlike me.
You'll need a new chain and probably will want to swap out the front sprocket also. This will effect your speedos accuracy, which can also be remedied.
I had a shop do it for me and got my sprocket/chain kit from ebay. Actually worked great, I got it for the opposite reason as you, wanted better acceleration. The top speed was effected but that didn't matter much to me.
It lasted damned long, 3 years...especially considering I was too much of a newb to oil it. Ever.
There's always a trade off and if your raising your top speed, i.e. lowering your rpm at 80 mph, you'll lose acceleration throughout the gears.