Just purchased a MY98 5DR, have initially filled up with standard UL from the local supermarket, but am considering using SUL or possibly Optimax which I have heard great things about, would I expect to see a any performance benefit, and is it generally better for the engine long term?

Have also heard there may be a small fuel economy improvement also???

(Although I guess I didn't buy it for the running costs!!!)

Cheers

Should use at least SUL to stop det... It is recommended on here to use octane booster as well if it is a JDM import.

Forgot to say its a UK car.

I use optimax mostly:Dif not the SUL:) never UL:(.

You will notice the difference. There has been plenty of debates about optimax verses SUL + Octane Booster....
However I think everyone will agree not to use UL long term.
That said one tank full should not be to much of a problem.

Does this apply to all scoobys??

I have a sport and not a turbo.

It's nowhere near as much of an issue on normally aspirated cars, as there's no danger of detonation.

Sure, you'll notice slightly better throttle response, and maybe better fuel economy on a Sport, but you don't contend with the real engine safety factors that arise with the turbocharged cars.

Im running a uk wrx on optimax and octane boosters, 1 every 5 tanks. Awesome :) and it smells nice too :D lol

I've had my 99 Turbo 6 weeks and have only used UL, I know the previous from new owner and am sure they also only used UL.

Every thing seems fine, drive and sound great.

Will now change to Optimax Etc

The small extra price you cough up for optimax is well worth it - peace of mind, extra performance - and i have to drive a few miles to get the the nearest shell - so thats fun!

After running on UL and then changing to SUL or optimax I'd also advise an ECU reset so you get just that little bit more. It's well worth it and simple to do.

Spooner.

i WAS TOLD MANY YEARS AGO, THAT IF YOU BOOT IT UP A HILL IN FIFTH GEAR, THE ecu - oops - caps lock - ah, that feels better - anyway, the ecu will reset automatically for the new fuel - true or not???