Yep, I know what you mean - even with the small amount of mods I have done, I have already well and truly over-capitalised... well... I am not intending selling, so I don't care how much I spend.
M3? God I would love one, but I just CANNOT afford to get one - they are so expensive here.....
I have just purchased some Nology Plug leads from Pelican Parts over your side of the world. Waiting for them to arrive so I can see if they benefit as much as they promise. Apparently have a capacitor built into the lead that allows the voltage to build up until it reaches ionization point at the spark plug and then delivers the full whack... apparently promises 300 times more power....... and is 100% legal in the States - check out Nology HotWires
I have ordered a set and eagerly await their arrival... ooops... drifting a bit off-topic there - sorry