I'm shocked! You didn't wet blanket his choice of cars?
Dude, since no one else is going to be upfront, let me be brutally honest with you. Both of these cars are out of your league for now since you'll be working part time only. Let's talk realistically, at best you get RM20 per hour (at best!) and you work 20 hours a week (at best again). That's RM1600 a month at best without any deductions (EPF, Socso, food, etc).
A 40k car (2nd hand) will have about 3.3% interest rates, and assuming it'll be a 5 year loan, with your dad paying 10k downpayment (awesome dad btw), that means your loan will be 30k.
So calculations :
Interest for 5 years = (3.3% * 30,000) x 5 = RM4950
Car loan = RM4950 + RM30,000 = RM34950
Monthly instalment = RM582.50
That leaves you with RM1600 - RM582.50 = RM1017.50
So say your average travel distance per day is 50km, times 5 days is 250km per week. These cars aren't exactly fuel friendly cars but I'll give them benefit of the doubt and give you 10km/L and I'll just estimate they have 40L tanks. That's about RM74 a week (you won't leave it until empty to refill right?) meaning RM290 on average for fuel per week.
Meaning you'll be left with RM1017.50 - RM290 = RM727.50
If you take away food (average RM10 a day for lunch, skip BF) RM200 a week that leaves you with RM500 odd loose change.
That's barely enough to replace the battery for the beemer, much less the parts you'll need to replace with the age of those cars. Of course there's the exception where you buy a car from a brother who completely overhauled the car and fixed all outstanding things before selling to you. If yes - then great... but these are old cars. There'll always bound to be something he forgot to fix.
I'm not familiar with the BMW nor the Tezza, but the S60 Volvo I do know. There's these joints in the front suspension that make a helluva racket after some mileage (about 20k km odd) and need changing. Those joints are RM180 a piece without install. So that's RM360 gone leaving you with barely enough money to buy a girl a meal. I mean come on, you buy a car like this for two reasons :
1. They are awesome cars and you just wanna own a piece of awesomeness
2. You got a hot chick you wanna impress
And with the amount money left behind #2 is kinda hard. And breaking down in an awesome car with a hot chick in it is not awesome.
So if you're insisting on buy either one of these cars, I'm thinking the only solution is to have a higher downpayment or minimally 25k, then find that high paying part time job that I was talking about (RM20 an hour) will be another matter.
Dude, you're better off with a new car la. I personally hate the Myvi even though I own 2 so I would totally discourage you from buying it. If you wanna get a cheap car get the Persona LE, for RM40k+ you can get a new car. Or if you can top up your budget, the Preve LE, that one is turbo goodness with the manual option. Plenty to mod on both these cars but less gaya mutu keunggulan compared to the beemer and tezza. But less headaches since parts cheaper and less parts to fix.
My 2 cents. Don't mean to be a wet blanket.