you can delay renewing the road tax + insurance as long as you don't drive the car la. no penalties whatsoever.

you can't get a roadtax without renewing your insurance, you need to submit an insurance slip together when doing your license renewal.

If you drive without roadtax + insurance, and you're stopped, its a RM300 fine if i'm not mistaken. But the bigger problem would be the insurance. If your car is stolen or you're involved in an accident and you don't have any insurance, you won't get any compensation. You'll have to pay for your own repairs, or in the event it is stolen, well, you won't get back anything - and you'll have to continue paying the bank for the loan even if you no longer have the car.