Hi there, I have a 2002 Honda f4i, and after reading every review on the internet, that told me the yoshimura was good for a couple of extra bolt on hp, and a great sound... I bought a carbon fibre rs3 on ebay. After installing it with a six pack and kicking it over, I had a grin bigger than texas... this thing sounded great. But I wasn't going anywhere except to the fridge and the lounge that night, with another beer and a remote control. The next day when i rode out of my driveway, my grin started to fade... f*%$ me this thing is loud!... I mean it sounds great, but have i just painted a target on my back?!? I decided I should be a little conservative on the throttle till i get out of suburbia at 6am on a Saturday morning. Then i found something that wasn't mentioned in any article or review i've read online... not only at low revs, from around 3-4000 rpm, (from memory) does my once puring cbr seem to choke spit and splutter... but where the hell did this flat spot come from!!! wind the throttle on gently and it doesn't want to know about it, but open it up enough and it launches. I got on the M4 to see what happens in a straight line, and my grin started to return. But the pros didn't outweigh the cons. I called my local honda dealer, and asked if they could remap the stock computer to suit the new exhaust, and the short story is that they couldn't. I'm still unsure if 'THEY' couldn't do it, as in the staff didn't have the knowledge how... or if it simply cannot be done. They did suggest an aftermarket computer, but that was going to cost me another $700 or so... Now the stock pipe is back on, and my hondas alot happier... and alot quieter. And the yoshi exhaust is wrapped in a blanket in the garage. I dropped into a yamaha dealer the other day, and asked if they had any thoughts on the flat spot so that i might try and put the yoshi pipe back on, and they suggested a k&n filter to solve the problem. I smiled and said thanks and walked away, thinking that all i need was a $140 air filter that made my bike run lean, therefore hot and with a flatspot and cranky low rev range. Now that you know my 'entire' story... do any of you have any ideas or experience with f4i's, yoshi rs3's, remapping existing computers, or aftermarket computers, aftermarket air filtersm and whether the end result is worth the effort in the first place... thanks. the joose.