Help me pick a money pit

Hello!

For context, I (27m) have a decent job earning a few thousand, close to 100k per month. I have had this job for more than a year. This will be my first car.My budget is 300k - 350k.

The first option is an MR2 from a friend, which has been sitting for more than six months without starting. He tells me it needs an engine rebuild. His asking price is 300k, and the plan is to negotiate the price so I still have a budget for rebuilding the engine and changing the transmission to manual.

The second option is to either buy an E46 318 or 325 and change it to a manual transmission since it's rare to find a manual E46 318 or 325. Alternatively, I could buy a manual 316 and do an engine swap in the near future.

Lastly, I could just buy a Camry with a 3.5 engine for speed and comfort, which would be a less of headache.

My questions are: Is it expensive to rebuild a non-turbo 3SGE? Are BMW parts readily available for PMS and modifications without breaking the bank?

Thank you for your feedback!