There is a thread in the for sale section on the forum about the PCD and offsets for the wheels here
http://marcosforum.org/reply/14071#reply-14071
The front and rear offsets are different - If I remember rightly the front is Peugeot and the rear is Ford
N.B. There is more metal on the front inside wheel hub ( to clear the front calipers)
Ronnie Cowan gave me these PCD sizes
Mantara & Mantaray buyers need:- 108 x 4 (PCD) requiring two x 17 Et + two x Et37 (ET=offset)
or four x Et37 & a TUV 20mm kit!
So I think the ET 37s are Ford (rears) - which you need a 20mm spacer kit to be able to fit them on the front
The recommendation for tyre size is for 215.400 x 17" Tyres.
The max size wheel and tyre combination I can get on my Mantaray without body mods are 17 with 225 x 40 in the front and 235 x 40 on the rear
That said both front and rear have rubbed the inner arches at times so the 215 x 40 size is probably right

