Q. I have finalized on getting the Street 180. Is the self start issue a real concern, is the fuel indicator working properly or there are any other issue with the bike that is serious

If the fuel is below half turn the fuel switch upwards and above half switch it downward. I faced a great problem a couple of days ago. The bike didn't start and the bike's battery discharged completely. There might be some garbage in the petrol pipe. Just blow some air in the pipe and when the petrol starts coming start the bike in 3rd gear manually by pushing it

Self start is a concern as there is no kick start facility when the battery goes down. If you don't use your bike regularly, better don't buy an avenger.

No issue with petrol gauge. Bike has manufacturing defects. If your bike does have, company will replace the parts for free. Mine were replaced.