I have a 2005 rx8 6speed M/T ~95k miles.

Since I've had the car the transmission has given me problems including the following:

Cannot shift into 2nd or 5th without grinding above 6k~ rpms.
Cannot shift into reverse without force/reving and still causes grinding.
High RPMs in 2nd gear cause an awful grinding sound.
Over-all excessively stiff shifting.

Currently my engine has failed and is being warranted by the dealership and so I thought it would be a good time to fix the transmission as well but here are my questions:

Would it be best to have the transmission over-hauled or would it be better to try to find one out of an 09+ or one with light mileage? If anyone else has done either of these, what are your experiences with cost?

I'm leery about buying another used transmission because for all i know it could have had the exact same damage and wear that caused mine to fail to begin with.

Also, what is causing all these transmission failures?? I've heard it theorized that the clutch-pedal flexing/failures are a large contributor which makes sense. I recently had my clutch pedal snap off and when I replaced it I went ahead and got a reinforcement bracket to go with it so that B.S. wouldn't happen again.

Over all I'm very disappointed in Mazda's craftsmanship on these vehicles and sad to say it because I absolutely love my rx8... I just find the level of massive failures on them to be unacceptable and I know that Mazda is capable of much better than what they've given us in these year-model rotaries... Anyway, thanks in advance for any information. You guys always seem to have an excellent knowledge base.