You might have picked up on this completed consultation from the government about MOT exemption - the consultation documents are here: https://www.gov.uk/government/consultations/roadworthiness-testing-for-vehicles-of-historic-interest Essentially they are going to introduce a rolling exemption for all vehicles over 40 years old from having to have an annual MOT. (Personally I think this is a stupid idea and I'll still be submitting my bus for an MOT every year as you can do so voluntarily.) Anyway, there is something that caught my eye regarding the issue of modified vehicles. The MOT exemption does not apply to vehicles over 40 years old if they are considered to be "substantially altered", and these vehicles will need to continue with a compulsory MOT test. The DVLA doesn't have a definition of "substantially altered", but it does define "radically altered", which are those vehicles that require re-registration, IVA test and a Q-plate, based on the '8 point test': https://www.gov.uk/vehicle-registration/radically-altered-vehicles However, the consultation I mentioned above includes a document that defines "substantially altered" for the purposes of MOT exemption, here: https://www.gov.uk/government/uploa...ical-interest-substantial-change-guidance.pdf Interestingly there are 2 criteria, and it's the first criterion that I think affects many of us with Subaru conversions, or in fact with any engine which is significantly more powerful than the original: My bus rolled out of Hamburg with a 1700 type 4 engine, which I think was around 60-something bhp. It now has a 2 litre Subaru engine, which must be around twice that at least. I think therefore it may fall foul of this definition of "substantially altered". However I'd think that there's quite lot of VWs, Bugs, Buses, etc that have even just had more powerful air-cooled engines fitted that would also fail this test - thinking of the 2056's, 2232's, turbos, etc that I've seen in people's beetles, for example. I'm just throwing this out there for comment because I'd love to know how they think they're going to administer this, apart from relying upon the honesty of owners?