Ok here goes. This is based on experience. Long reply.. plz take time to read.
1. You can drive a MH car in Bangalore provided you pay the Road tax. Now there are two things to consider, you can either pay lifetime road tax or you can pay for a year. Paying for a year is based on the fact that you want to take your car back to MH in a year's time. If not you can pay the lifetime tax.
Now comes the formula (this was 3 years back). The % might have changed.
Tax is calculated on the Invoice value of the vehicle and the age of the vehicle.
Check out this link
New Page 1.
The way its calculated is
total value of the vehicle (base value + vat) * (9% or 10% or 12% based on car value) PLUS 5% cess on the above tax.
Now if your car is less than 2 years old its 93% of the total tax. look at the above link for full details.
Ex. If car price is 4,00,000/- than tax at 9% for santro would be 36000 + 1800 (5% cess) = 37800/-
Less than 2 years 93% = 37800 *93% = 35154/- (approx)
I'm not sure about the cess value now.
Hope my maths is right. This was how my Matiz tax was calculated when I got it from TN.
2. Now to change the Registration there's another procedure.
You have to get NOC from your original RTO in MH. For that you have to give a covering letter, fill up a form, insurance copy, pollution certificate, sometimes license copy. Also make sure if you have an hypothication, get it cancelled. This has also caused us problems.
Now come's the tricky part, once you get it, you can apply for a reimbursement of your MH Road tax. You should apply this within 10-45 days of getting NOC. This has been varying at times and I've been unable to get it. As someone pointed out, its too tough to get our own money back from the govt.
Finally make sure to get your car registered in KA as soon as you get your NOC. You would need the same documents as above (pollution, rc, insurance, letter from bank if loan is done, etc). I suggest you become a member of AAA and get it done through them. Its 3500 for membership i think. if not you would have to pay some nut agent. Or if you know kannada you can go directly to the rto and get it done yourself. I suggest you take a kannadiga friend for help.
Read below if you want to know what can happen otherwise.
Also we ( me and my friend) landed up in another problem. we got the noc but did not change the number here in KA due to various reasons. Recently when we tried to change it, the KA RTO says that the NOC is valid for only 45 days. They asked us to get another NOC. We went back to the TN RTO and they say that they cannot issue another NOC coz when they issue an NOC the registration of the car in TN is no longer valid !!!
Also when we got our NOC we had not cancelled our hypothication. KA RTO asked us to get it cancelled in TN. TN RTO says they cannot since they have already issued an NOC.
We approached AAA. They said that within 45 days of an NOC being issued you have to get the KA registration done. They had asked for another NOC. So we are back to Square ONE !!
So in short we are driving a car with no legal registration it seems. If someone has a solution for this please let us know !!!