All high performance modded cars are subject to more breakdowns and maintenance and cost a ton of $$.
Keep your car stock and drive easy on it so it will last a long time. Then save your money for an M3 or maybe college so you can get a good job and buy an M5 someday.
Just my .o2
2004 E60 530is, Delivered 12/12/03, TiSilver/LGrey, PP, SP,PS, PDC, ACC, FRS, Step, Xenons, clear bra, body colored rear inserts. (Retired, 1983 henna red 320is)
2004 Corvette Z06 Commemorative Edition