I just got an MR, now with 300 miles, and I'm looking to make some conservative upgrades. I've read that you should wait until 1500 miles to do anything. Anyways, what I plan to do is have my ecu reflashed by Vishnu and possibly adding a cat-back exhaust. According to other posts, adding a cat back will not require a dyno tune.

what do you guys think?

dont really need to wait... after run-in (break-in) will be fine