The TDs are always faster. Why? Better aerodynamics and weight distribution. Don't believe me? Well, because its probably not true, but I like to pretend.
Also, silver is the fastest color, something about light bouncing off of the tiny metallic particles and speeding you up.
Seriously though, my TD is quite quick, actually more powerful than I thought it would be! The ALDA has been tweaked up a bit, and everything has been cleaned out real nice with a good valve adjustment. Purrs like a big huge kitten, and pulls like a freight train once that turbo kicks in.
In WRX rally racing the wagons are actually prefered by many because of a better rear end weight distribution, but on our 300s, I doubt it makes any difference.
Theoretically, the two vehicles should be almost indistinguishable in performance, if the TD is much slower, I'd start looking for problems like others have suggested.
Peace,
sam