You do need to change your plates over within 10 days if you want to be legal. Emission testing for gas rigs is $68.00. For the Diesel you will need to take it down to the Borough and they will have you start it up so they can listen for the diesel rattle and then they will slap a Diesel Exempt sticker in the window. The exempt deal is a one time deal but the gas rigs have to be retested every two years. For The tags it will cost you $100.00 for two years. When you renew if you don't do it on-line or by mail there will be an additional $10.00 charge for walk-ins. There is also a $2.00 IM administrative fee for gas powered vehicles. You can visit http://www.state.ak.us/dmv/dmvhome.htm to get all the required forms and information on your drivers license and vehicle registration.