Mk2 and 2.5 Differences

Hi, what I need help with if anyone could provide me with the info

Will the mk2.5 exhaust back box fit the mk2?

are most if not all parts the same on the mk2 and 2.5?

Thanks Darrell

Hi Darrell

The MK2 and MK2.5 may look similar but there are many differences. Having said that the engine is the same on the MK2/MK2.5 1.6 but totally different with the 1.8.

Your question with the back box is a good one. I suspect they are interchangeable although Klarius list two part numbers…

They are around the same price so unless you have been given a MK2.5 part, I would buy the correct one.

PM me if you want further guidance. 

Mk2 and mk2.5 rear boxes are the same presuming it has not been cut /welded before etc. Centre sections are different as is front pipe but rear boxes same

Just bought a Mk1 and want to change the cloth seats for leather, but only Mk2 leathers seem to be for sale, so do Mk2/Mk2.5 seats fit a Mk1?

Yes, they do fit and due to rarity of good MK1 leather seat availability, likely to be your only option.


Klarius are reckoned by the trade to be the best resource for exhaust specifications. Having said that they list the later MK1 short cat(435mm) with the short catback(1590mm) and the later MK1 long cat(475mm) with the long catback(1640mm). Full marks to Klarius for getting it completely and confusingly wrong and not correcting their catalogue as requested some years ago when their misleading listings caused me an issue.

Klarius list the MK2 backbox with a different OE part number and Klarius part number to the Mk2.5 but I suspect the parts are interchangeable.

MK2 have front pipe, cat combined with middle box and back box

MK2.5 have a front pipe and cat combined, middle box and back box.

To confuse matters some early MK2.5 cars have a MK2 exhaust configuration.

MK2/MK2.5 far easier to supply for than MK1. I advise all MK1/Eunos owners to check and measure their exhaust parts(cat and catback) before ordering replacements.     



Didn’t manage to get the used box in the end but did manage to get a centre box and back box for £95 brand new ok it was euroflow and I have to cut the original pipe and remove the cat to slip it into the centre pipe but its all on now and the back box had a chrome tailpipe already on it quite surprised by the quality usually the fitment is bad but this was pretty good for the money thanks for the advice

Thanks for the Info, got a good set of Mk2 leather seats and fit perfectly and greatly improve the interior.