SRAM TT shifters 500 vs 900

Is there any real dirfference in these shifters other than one being carbon fiber and lighter?

Can’t decide which ones to get, but I need to get some soon. The weight difference is not a concearn to me as I could stand to lose about 13,000 grams of weight myself.

I was more wondering about shift performance.

Right now I have the R2C’s, but I switched from an s-extension to a ski bend and I think I like the function of a regular shifter on the ski bends, and a tension shifter for the FD.

I was thinking of just doing the FD, but I might as well do both and pay for it, or even put some money back in my pocket selling the R2C’s.

I believe weight is the only difference. I had the 500’s and they worked fine. Just switched to R2C, and obviously that is a different feel, not better or worse.

they are the same other than weight.