Another vote for Ultimate. I've used it since my CA conversion and never had a drama. I've haven't tried the other fuels as a result.
Matty

using ultimate or synergy8000 (both fromthe same refinery in melbourne here with a slight detergent in the mobil added post production).
Ultimate gets my vote, my carfouls plugs on optimax too, and detonates with carb back firing on vortex 95... cant wait for vortex 98 in melbourne (have to wait till march 2006 acording to caltex head office).

have heard good things about vortex98 from nsw people with boosted cars

looks like I'm going to be switching over to Ultimate 98 as well then after all of this... the only other thing I've been told about Premium Unleaded is that it goes off a lot quicker than normal fuel - can anyone confirm this?

Ive run all of them in my 10.1 to 1 A14 and havent noticed much difference between all of them. BP is supposed to be the best but I believe (no real testing) That i get better fuel economy out of Shell Optimax. Plus its often 5 or so cents a litre cheaper than Ultimate.

Here's another vote for BP Ultmate...that's what I use in the Sunny.

Safeway all the way
Nah only joking.
I have tried all except the vortex.
I have a A14 running 10.6:1 comp. I can run normal premium but there is a noticable differance when i use optimax & a bigger differanc when i use synergy or BP ultimate.
What type of plugs do you guys use. I have never had any foweling probs but i use iridium plugs.
I have started using a octain boost wich you race guys might no about that uses real led. Alot of guys racing historic classes use it. I cant think of the name right now but i will let you no.

My plugs fouled running BP Ultimate + a carby/carbon cleaner after idling for about 10minutes. But that what happens when twin SU's mixtures play up. All sorted now and running optimax and plugs are clean. Im running a heat rating 5 plug at the moment(standard) and was running a 6 but it was fouling worse when the carbs were playing up. Could probably get away with them now quite easily.