wow, nice group, i dont come on here much, but this is awesome!..
I've got a SGM 130i, with Quaife LSD, 135i front brakes, BMS powerbox, and CDV, and the KN filter from the intake :P (went the cheap option)
lol yeh, can't do much else to our ole 130i's.
Other mods as other's have mentioned are:
some ppl get the M3 suspension bits.
I've seen the blue port melbourne 130i zipping around couple of times :P, i'm normally heading down hoddle, and around port melbs in the mornings.