What is the difference?
 

Which driveshaft is better? the stock oem, or the aftermarket driveshaft on mazdatrix? I heard that a lot of the time its not good to put aftermarket parts on, in replacement of stock parts, cuz it could potentially be worse for the car, so will the aftermarket driveshaft be worse or better?

I would go for the aftermarket shaft because they have replaceable U-joints.

The aftermarket one will probably be fine, but I'd go with the OEM. As far as replaceable u-joints, if you just drive on the street you'll more than likely sell your car before they ever go bad. Now if you're super hard on your car, or take it to the track, you may want to go aftermarket.

The aftermarket Mazdatrix sells is cheaper than stock.I personally would go with it. Also I don't know about other people's experience but I've been through 3 used ones along with my original one. All the used ones along with my original one came from cars with more than 100,000 miles on them. What I'm getting at is I would expect to get between 100,000 to 150,000 miles on the OEM one so if your going to keep the car along time and potentially put that many miles on it you may want the one with replacable U-joints.

Yeah cuz i don't plan on selling my car, this is my baby! haha, I got her about 3 or 4 weeks ago, and i'm too much in love with it! haha!

I've never really had a problem with a u joint failing, but I do like the sounds of a lighter and more balanced driveshaft, with replaceable u joints as a bonus.