NOC necessary only if you want Karnataka Registration. This is useful only if you want to go for some exchange scheme or sale here. Else just need to pay road tax and register local address. Road tax calculated as per guidelines, based on year of manufacture. Penalty for late documentation depends on your ability to convince that the vehicle has just been transferred to Bangalore . Other documents like PUC, RC book/slip, Insurance are any way necessary. Both registrations take @ 1 working day. Better take leave from office/work. Ensure that engine and chassis no. are clearly visible since they are verified w/o compromise by RTO in person. Other details of procedure available at RTO offices.
Requirements For Karnataka Registered Vehicles
As far as possible clear loan if any and get form 35 signed by financer. Clear RC book from hypothecation. Get insurance policy redefined. Locate new RTO office. Apply and get NOC from current Bangalore RTO. Register vehicle at new RTO. Get new RC book and tax receipt. Based on these 2, apply for Karnataka road tax refund.