If the "Iceman" crossmember supports the transmission in a drag car, then it must be decent enough for a regular duty vehicle. However, aren't those the ones that are a thin, round tube?
If anything, adding weight in the frame is not a bad idea. People put huge trailer hitches on because it supposedly ties the rear frame rails together. The G-Force, Jegster, Summit, etc. crossmembers are not that heavy, definitely not as heavy as a lot of trailer hitches.You won't lose any noticeable gas mileage, it won't make the car considerably slower, but they will make the chassis stiffer and make the car safer.
Basically, if you want a drag car, the "Iceman" one may be the one to consider. On a daily driven vehicle or on a car made to handle, I would go with the G-Force or similar piece.