I have a my00 uk turbo which was standard when i got it, i have fitted a ppp ecu, magnex down pipe, panel filter and scoobysport back box, i have kept the middle cat in for now, i allways run it on optimax or normal unleaded with octane booster because the nearest optimax is about 17 miles from where i live. what i want to know is will i see any benefit from running it on optimax plus booster taking it up to 99ron or can you over do it with the booster and it should be run only on 97ron

 

dont think you'll see much benifit tbh mate, 97 should be fine for a UK car and should be the most effective.

optimax is already rated at 98.6octane so thats already higher than the normall super unleaded which is 97octane. if you went any higher you will most likely pink or similar.

 

I was just going to say Optimax is 98ron not 97, I pretty much sure BP is 97ron, I know that Tesco have brought a new 99ron out but its not up my part of the country, they done a test and Shell Optimax 98ron is actually better than Tesco's 99ron.
I'd stick with Shell or your booster with super unleaded, after all your car isnt a Jap import and wont have been set up on High Octain like in Japan with there 100ron, I know one of my mates with a Uk WRX can run his car on any petrol were as my car will missfire or die if I dont use the good stuff due to different ECU/fueling set up