I don't know

You turn your back for a minute and everyone takes the p!ss out of you

This is something I'd never do to anyone else on here

Edition30 - sure 10 pots normally have ££££££££££££££ signs all over them, but I was offered them fitted for £1k and so it would have been rude to refuse. What RR and Tom have said about 4 pots being all that is needed is probably true and I would recommend them, but they are relatively expensive too. An R32 conversion for the front is the cheapest way to get a decent upgrade, but again there is a small penalty with loading up the unsprung weight of the car that goes with it.
There are a few companies doing aftermarket exhausts for the ED30 and I think that I would only entertain a Milltek or the APR versions. Going for a cat-back only will get you added sound, but that is about all you will get. The extra power and sharper throttle reponse comes from opening up the downpipe and getting the high flow sports cat.
Tom is just about spot on with the diff options, although peloquin is a little cheaper than Quaife.
ARB's are a real transformer of the handling and feel of the car. I have Autotech lightweight ARB's both front and rear. The emphasis needs to be made that altering the ARB's can alter the balance of the car and either make it understeer less or more. I feel that it makes the car more agile and stable, with a better turn in and exit feel from corners.
Suspension mods, Induction kits, Forge DV, Torque arm insert, intercoolers...the list you could go for is quite extensive really.
