Newbie, please help

Hi fellow BM Fanatics, I'm new to this forum and in some great need of help. I'm looking at purchasing a BMW 540i (E34) and I'd like to find out what the availability of the parts is like? Ideally I'd like to buy one, put some lower stiffer springs, mags, some M trim, bucket seats, Free flow pipe and headers, aftermarket ECU chip and maybe convert to MAF? Love the sound of the V8 and dig the look of the car, what do you guys think? Not looking to race or anything, just looking for a b*tching BM that I can daily and mess around with. Or should I stick with a 325i E36? How's the maintenance and aftermarket part availability on both cars?

Thanks in advance