I say buy the car that you know you can barely afford...you wont have money left to burn on mods so that wouldnt be a problem and if you ran so short on money that you couldnt keep the thing and it was reposessed there goes any boredom factor
honestly though I saw an ram srt-10 going for like 39 grand...its a truck with power and a price tag that screams "i wont be able to mod it" just my o2