Probably no legit reason, honestly. I didn't weigh them but not sure if there is much significance in weight. The stock front tower hugs the diff housing with some nice support fittings, where as the carbon tower just sits flat/flush w/o the contour around the mount holes. So all in all probably not an advantage to going to the carbon, in most instances. I honestly just didn't want to upgrade diff gears or do anything like that. So I just did some easy stuff to potentially lighten the car for 13.5. And the spool was just something that I wanted to try, after hearing some good reviews. At the end of the day, at club level, for me it comes down to the driver and the fun. So I just wanted to try a few things.