Disabling these functions with Techstream will disable the automatic-telescopic and auto-tilt only. You will still be able to make manual adjustments.
Alternatively, you can totally disable these functions (auto and manual) by removing the power to the motors. With the car running, adjust the telescopic and tilt to the desired position. Leave the car running and pull the 20A fuse called TI&TE in the driver-side fuse box (see diagram below). Just put the fuse back when you want to restore these functions.