A
Th
the Bypass still helps eliminate the torque management.You don't "need" the bypass if you have the TL, It will provide some redundancy in case the i4WD goes out but it won't do anything different than the i4WD switch. As a matter of fact, you lose a couple features with the bypass...
The bypass only engages the front diff clutch
i4WD engages the front clutch, enables the traction control (but really only anti-lock brakes) and enables the power steering boost.
With the TL, the i4WD traction control is still active but it no longer does anything because the front tires will no longer spin at different speeds.