This is a brace that welds inside your transmission bell housing going around the input and intermediate shafts. This serves to reinforce the housing and help prevent the shafts from pushing themselves apart as power is applied. This is particularly important in mid- to high-horsepower cars. The transmission gears' natural tendency is to push themselves apart. Reinforcing the transmission case helps prevent this.
Click for a larger picture of the brace installed in a 6-speed.
Obviously, you will have to disassemble your transmission as this brace is installed on the inside of the bell housing.
Available for AWD 5-speed or 6-speed.