Originally Posted by Big Vern
Jap spec are generally the most powerful variants (Generally only US spec cars are lower powered)
1.6l JDM Would have left the factory with 113bhp on low octain fuel
Cheapest mod is to raise CR to 10:1 to make use of uk normal unleaded fuel.
Probably only worth a couple of HP but make it sharper and more responsive.
Beter exhaust manifold and a K&N filter so long as you keep it away from exhaust heat - not easy in the normal mx-5 as the underbonnet temps can get pretty high:0
The engine has got a K+N filter just now, there is a metal shield around it to try keep the hot air away and a has a vented type headlight on the passenger side.