I think that if you were going to undertake a type rating over here the company which is organising the TR would be able to keep you informed regarding immigration status.
I wouldn't recommend anyone to take anything read on PPrune as truth especailly regarding Immigration issues. The US Embassy is just a phone call away and if you email the INS they are normally pretty good at replying.
If in doubt, check!
M1 - Normally non academic study in the US, which has a limit on the maximum length of the visa - could be 6 months - check.
J1 - Exchange visa which also allows you to work generally in the field assocaited with the visa. Normally 18 months, for flight training this can be extended to 24 months.
Your school should be able to help you with any questions you have. Ask to talk to the approved official if your answers aren't detailed enough - if not contact the INS - or whatever it's called nowadays.
More information can be found on the Immigration website regarding students.
http://www.ice.gov/sevis/students/index.htm