Private leasing companies

Assalamualaikum, need advice. How's private leasing companies are in Karachi? Scam or legit? I was thinking about leasing a car and bank only limits the tenure of instalments on 3 years, I want for 5 years that's why I was thinking about private financing, are they trustable? They have markup of 8% yearly. The procedure they told me that after I give them down payment, they will take 4-5 bussiness days to hand over the car to me. Jazakallah.