can la 4k... but old or not to old sportr car la... but make sure u got at least 10 to 45k deposit 1st... car i suggest to u is like Celica, Airtrek Turbo, Altezza, MR-S, Evo 4, 5, 6,7 , Subaru Ver 4,5,7 , Silvia S14, 15, 180sx convert, Rx7 enfini, Rx8, Caldina GT or NA, FTO, GTO.... or Honda Civic EK3, Intergra DC2... and better if u stay with ur family so more money can be save to maintain the car.... to reduce cost for maintaining a sport car ..at least u must know how to find cheap parts, know runner, buddies to halfcut towkey and know a little or more about repair car and can do it by ur self oso for minor problem....hehe
btw not too high spec tyre for silvia 18in rim brand new will cost u RM600 each, cun one will cost u nearly 1k each....
- in same time try find extra money from ur extra jobs..maybe u can be a parts runner or sell things on e-bay...:)