Mods are OUT
A vehicle that has been substantially changed within the previous 30 years will have to be submitted for annual MOT testing – this 30-year rule will roll on, just like the 40-year rule for MOT exemption. However, there are a number of exceptions, which concern engines, the use of alternative parts where stock parts are not available, and upgrades to the brakes and suspension in the interest of safety or the environment. See the appropriate sections for each area of exemption. Remember that this only concerns substantial changes. Fitting non-standard door mirrors, for instance, does not affect MOT exemption.