You're talking about the "what ifs". Fact is, you don't have a monthly car payment.
You want to have a car payment AND spend money modding it? How does that make any sense? You said yourself that you are tight on money.
'09 LCI 335i E90 in BSM over Oyster Dakota Leather, 6 spd, Sport, Navigation, Individual Audiophile, Executive, Active Steering, JB4 + MHD BEF, 335is Exhaust w/AWE Tuning Tips, AFE DCI, Euro Tails/Fog Light Switch, various painted and other OEM + mods, 19" M5 reps summer, 18" M6 GC reps winter.