If you have a single turbo you need to put it in the down pipe I think the instruction say 18" away from the turbo and no lower than a 3 O'clock or 9 O'clock angle depeding on which side of the exhaust and the sensor will last longer but a slightly slower response time. You can also mount it closer but it will shorten the sensors life. I install mine at a 2 o"clock position.
TT setup I would think you would want 2 widebands.
And as the other guy above said a WB02 goes in the exhaust.
96 GT 70mm Hairdryer SCT Mass, SCT tuner.
03 Evo 8 GT3076R, 720 inj.,3.5" IC, 272 cams, SMC alky injection, 3" TBE. Dynoed 420 hp 400 Tq.