I run a T3R with alu turnbuckles, geardiff, steel- and hardened alu driveshafts and antirollbars. As long as you are not fighting for a national or a world title, this car is easily fast enough. The thing is that you may upgrade the T3R with some rather important parts for serious racing listed above (mainly to have to spend less time for setting up the car). After that you won't have a problem with all that 'carbon arrows'. Sure, there is the point in driving skills from where a full spec race car will be faster but that point is situated very high.
If you look for car performance only then you should go for the T3'12 instead of your T3R. But, as said, most drivers on this planet will be the same fast with all those electric touring cars if they figured out a propper setup.
What I noticed at our track was that lots of drivers switched to the T3'11 last year and were faster from the beginning because of its ease of setup and driving they told me. Those ran Tamiya and HB previously. To me that shows that Xray TC cars probably are easier to set than some others.