'Still, a V-Rex benefits from one if it's shaped properly'
It is true there is a benefit with a faired SWB but not as great as the LWB TE. Alone I do not think it is worth it on the SWB. You have to weigh the cons (extra wt. and harder to transport) aginst the pros. (cost, aero, warmer, necessary with the body sock, looks cool)
The TE was made for a fairing. I feel naked without it and with the body sock you can ride naked!
There are statistics from trials with fairings on the TE. I think it is around 12% increase efficientcy dependent on the test speed.
http://www.pghs.org/science/rubin/bike/
http://www.easyracers.com/vbb/showth...hlight=fairing