First of all, for 10-12yrs old sports car, can you still get 7 years loan? Then also can still get only 3.7% rate? Genuine question here coz I'm really not sure. Probably a more realistic installments would range in the 4+k/mth just to be a bit conservative.

Yup installments is one thing, maintenance is another variable which can be even more unexpected especially for used supercars like this. It can hit you with a sudden smack of few thousand dollars if something goes wrong with it. I think income of just rm10-25k is not really suitable to own such supercars yet. There's some popular general guide that if you want to buy a car, you should have at least an annual income equal to the price of the car when new. But again depends on how you manage your finances.