Mobile vs mail-in DME unlocking

Posting your ECU across the country is the normal way to do this. It is not the good way.

The standard way to get a DME unlocked is to remove it yourself, box it up, post it to a workshop several states away, wait, and reinstall it when it comes back. Thousands of people do it every year and most of them get their unit back fine.

It is still worth understanding what you are agreeing to, because the alternative is not obviously more expensive and is meaningfully less hassle.

What mail-in actually involves

• You remove the control unit yourself, correctly, without damaging connectors that are not cheap.
• The car is undriveable for however long the round trip takes.
• Your DME is in the postal system, insured for whatever you declared.
• You reinstall it yourself and hope the car starts.
• If something is wrong, the person responsible is a support ticket rather than a person.

What mobile involves

Someone comes to the car with the equipment and does the work where it sits. The unit is never removed, so there is no shipping, no downtime and nothing to reinstall. (The one exception we make is the S68 V8, whose DME9 units cannot be unlocked in the car at all — so for that engine the DMEs have to come out, and we say so before you book.) You are present the whole time, which also means your original data is backed up in front of you rather than described to you afterwards.

The practical difference is a car you can drive that evening against a car on the drive waiting for a parcel.

Where mail-in still makes sense

If you are nowhere near anyone who does this, mail-in may be the only option, and plenty of the workshops doing it are good at it. It can also be cheaper on paper, though that comparison usually leaves out shipping, insurance and your own labour.

Questions worth asking either way

• Is my original file backed up before anything is written, and can I have a copy?
• What happens, specifically, if the unit does not come back working?
• Is my car actually supported, or are you going to find out when you try?
• What is the power supply situation during the write?

Any competent provider has quick answers to all four. Vagueness on the third one is the one to walk away from.