Insurance
In the UK a remap counts as a modification, and you should tell your insurer. Failing to declare modifications can lead to a claim being reduced or refused. Some insurers will cover a remapped car at no extra cost, some will add a premium, and some will decline. Ask before you book.
Manufacturer warranty
A manufacturer may refuse a warranty claim on an engine or transmission fault if it considers the remap to be the cause. Whether that applies depends on your warranty terms and the manufacturer. If you are under warranty, check the terms first.
Remap Experts guarantees
Remap Experts remaps come with a 30 day money back guarantee and a lifetime software warranty on the remap itself. This is separate from your manufacturer warranty and your insurance.
DVLA and MOT
A remap does not normally need to be recorded with the DVLA, and does not by itself affect an MOT, provided emissions equipment is untouched and the car meets the emissions limits.
How to approach your insurer
Call your insurer or broker before booking, say plainly that you are considering a stage 1 ECU remap, and ask whether it is covered and whether the premium changes. Get the answer in writing, and keep it with your policy documents. If one insurer declines, others may accept it, so a broker can help.
Selling or part-exchanging the car
Because the original software is saved, a remapped car can be returned to standard before sale. Some buyers and dealers are happier with a standard car, so it is worth deciding in advance how you will handle that.
Questions
Do I have to tell my insurer?
Yes. Tell your insurer about any modification, including a remap.
Will a remap void my warranty?
Not automatically, but a manufacturer may decline a related claim. Check your warranty terms.