Derestrict what? Before you go changing anything do you know if your bike is running to its full potential?
After reading through these forums it sounds like poor performance is usually as a result of buying a second hand bike that has likely been incorrectly adjusted or serviced and has developed symptoms of incorrectly adjusted carb, clogged air filter, high oil level, bad battery, over tight or slack chain and similar routine maintenance items that need attention.
"Derestricting" sounds like you want to remove anti pollution gear that besides being illegal and makng the bike difficult to resell will probably only make very modest changes to performance-if any difference at all.
