Noises while shifting?
 

While shifting, I hear a thump, the when I open the acelerator I hear a louder thunk, now I've been told it is the differential mount and, as I look at it the differential doesn't move, so what could it be?

possibly the u-joint on the axle. it could also be the exhaust hitting the underside of the car as the engine twists. i have that problem at the moment....

I was thinking it could be the exhaust hitting the underside also, yeah my friend was thinking it was the u-joint.....

My next question to whom ever is, how do you come about fixing a u-joint if that is the problem?

you have to buy a new driveshaft mazda decided to be assholes when they made it so you cant replace them but when you buy a new one from like mazdatrix you can replace the u joints on them

Which driveshaft is better? the stock oem, or the aftermarket driveshaft on mazdatrix?