You need to apply through the 15% All India Quota reservation in Chennai being a candidate of Maharashtra. 546 marks equivalent to an ALL INDIA QUOTA rank of 8466 was the cutoff last year. Having said this the cutoff keeps fluctuating from year to year as they depend on various factors like number of candidates appearing and also the paper level difficulty, etc. Also fro this year AIIMS and JIMPER are merged into the NEET examination, so the exact cutoffs cannot be predicted. But yes, try for scoring something above 560-570 and above to be on the safer side.

Refer to the following site for more detailed information..

https://medicine.careers360.com/articles/neet-cutoff-tamil-nadu

Refer to the following site for knowing more about Shri Ramachandra Medical college Chennai -

https://www.careers360.com/colleges/sri-ramachandra-medical-college-and-research-institute-chennai

Best wishes. Thankyou.