if i wuz u mate.....i'd get some 17 chromes, gt wing, respray jetblack, body work so u dont need to lower, sound system.
wat you can get for under $5ooo- 17'rims-$2000, decent head unit- $300, set of 4 speakers-$150, good quality amplifier-$700, 2x 12 or 10 inch subz in a box-$300, body kit-$1500