If you want more preformance than it can give you should buy a bigger more powerful machine.
You will not do anyone any favours by putting a loud end can on which will antagonise people and bring the TRF into disrepute while providing a small increase in top end power which you will not be able to use when laning anyway. Usually such modifications lose out on bottom and mid range power which is where you need it in the lanes.
If you are racing the bike and it will not be used in the lanes I apologise for the above, but noise is the commonest complaint about motor vehicles on green lanes and I tire of meeting people who have been annoyed in this way by inconsiderate riders
My standard silencer was heavy and not road legal (DRZ E..), I fitted a DEP tail pipe which meant it was then road legal - no performance gain, just quieter & lighter.
Though to be fair the title leads me to believe you are in search of extra power, which you aren't going to find by fitting a "Performance Exhaust" - that road generally only leads to noise.
As Pete has already said - more CC or a much more modern water cooled 250 will be the answer..
just get a full fmf powercore 4 system,rip out the dp killer. wont make that much difference, but sounds friggin awsome ! if people dont like noise, they should listen :)
OK the reasons i want one is twofold- i would like better performance and a lighter can will make sense for me. Also they look alot better than my knackered OEM one which is 14 years old! Most of this type of pipe are still quiet and road legal. I'm sure i won't be the only member that will have a non standard exhaust. I assure you Pete that my aim is not to annoy people or get complaints. Thanks for the other suggestions - have added them to my watch list.