I'm sorry to hear that. The 04-08s gearbox has had it's fair share of issues. Many people need their 2nd and 3rd synchros replaced before 50K miles. I had 2nd, 3rd, and 5th replaced.
The best thing I ever put in the gearbox was redline MT-90. So nice. I also shift into gear when the 'car is ready'....I also rev match as much as possible on downshifts.

 

yeah... eventually i'll put some nice gear oil in it, but let's be honest, a brand new car shouldn't behave this way. let's hope mazda makes good with this.

 

They might try to blame it on 'user error' but that's bullshit. If you take it back to the dealership they have to fix it under the bumper to bumper. It would be especially bull if you are still in the break in period and aren't driving it too hard yet.

 

yes, it's still in the break-in period. i haven't WOT or redlined yet. i'm sitting at around 1k miles now. hopefully they have good news for me tomorrow

 

That situation sounds promising. Good luck.