I need my registration (Road tax) renewed, on a 2 yr old car. I vaguely remember that for my license and first registration the wanted a copy of an immigration statement confirming my residence. Do I also need that to renew it now?At what stage do I need a vehicle inspection for renewing registartion?

To renew the Road Tax you will need the vehicles registration book and the CTPL (Government Insurance)

All you need is the Blue Book and some money. You can pay the government insurance along with the registration or "road tax." My car is 14 years old and I haven't had an inspection. Although after the vehicle is 10 years old, you can't change insurance companies for your A-1 or other grade of secondary insurance. As a farang, I still carry A-1 insurance just to cover my rear. My motorbike did require an inspection at 10 years old though.