[Graham]

I started measuring my own cars for another proxy, and then thought I might apply it as a test for our proxies as well. 
Basically our rules say the Max rpm as quoted by the manufacturer. So there will not be any penalties for cars with motors which out perform the manufacturers spec. 
But I will post the running RPM results I measured for the proxy cars when I have them all. And occasionally you get some entrants with motors without wrappers and a little vague about the motor grade, so could be useful to pick up any unintentional mistakes with those.
This particular car did have a motor with the Brand wrapper, so perhaps the entrant made a lucky purchase with this one 

The tyre width issue is also a case that sometimes the "intended tyre" does not end up exactly as stated, and often it is a case on measurement that one rear tyre is more swollen than the other, so one could be in spec and the other outside the spec. So you need to look at this in a pragmatic manner. But it is quite clear to me when entrants are fitting basically oversize tyres.