Have to declare some. The T3R is not designed for top of the line racing, thats the reguler T3 2012. It is desined for entry or stock, where rotating weight is very important. These alu driveshafts are mush better then other manufacturers I know. Those last for 2 runs, not more...
The larger diameter of the alu requires just a bit less dual rate.
The most important with driveshafts is maintenance. Always clean and apply graphite grease on the parts after every 10 runs. The whole assembly will last much longer.
The ECS has double joints with double maintenance needs, and the lighter pins can brake easily on bigger impacts. Its very good for asphalt tracks with long, fast sweepers, if you have it on your track, then its a smart option. In my opinion the best combination for serious racing is the normal steel driveshaft with alu outdrives and plastic caps.
"DO NOT use the plastic caps with composite solid axle included in the kit. The new #305241 3.5mm plastic caps are for use ONLY with GEAR diffs, ALU ball diffs, or the XRAY Multi-Diff." - This is like : " dont put your cat in the microwave when you want to dry him/her"