So, can NEXUS + GE members simply enter their car details on the online portal and have their vehicles ready for SENTRI? No more visits to SENTRI stations required?

To clear all doubts I am adding the statement from official CBP SENTRI FAQ

If you wish to register your vehicle after your initial application, you must pay a $42 vehicle registration fee. Vehicle registration is only required for use in the SENTRI lanes along the U.S./Mexican border. It is NOT required for NEXUS lane usage.

You can add/remove a vehicle for use in the SENTRI lanes through your TTP account. Please select add a vehicle from the Dashboard. After you pay the processing fee you will see it pending review. Please note processing times for vehicle enrollment vary vastly and it can take 3-5 months to process.

Upon vehicle approval, you will receive a letter stating that you will receive a new SENTRI card, please disregard. You can use the vehicle immediately upon approval with your existing Trusted Traveler card. Vehicle inspections are no longer required.

This page seems to have been updated 10/01/2017 01:16 PM