To the OP, I do not think you would like that combination. It will be underpowered and not feel great.
In Canada the motor vehical act passed in 2001 does regulate exceeding the manufactures ratings. It is managed in the act much like speeding, you go x over you lose points and can go to losing licence and heavy fines. In Nova Scotia, much like the speed limits, if your caught more then 30% over it is considered dangerous operation of a motor vehical. Speeding is a much more severe penalty with a law passed a few years back that removes it from dangerous operation to stunting managed under a completely different set of rules.
I know a few police officers and none of them are looking for over loaded RVs. There is a law against it but they more or less look for over loaded pickups with the loads in the bed. It would really need to be obvious to be pulled over!
I have not bought an RV where I have not signed a non liability agreement that dealer keeps in reference to the MV Act of 2001. Basically states I am responsible for the safe operation. Also my insurance, just like speeding, if I am ever declared dangerous operation of a motor vehical my contract with them is void.
The difference in the acts across Canada, different provinces do not appear to have the same definitions of dangerous operation of a motor vehical. The 30% is what Nova Scotia has. One thing that is common, never heard of anyone charged with an RV. I think with threads and such like we have, more people out there with means to voice concerns against it, you will see it policed more someday.
Europe also have very similar rules. No idea about the U.S. Head there in a couple weeks but I am well under my 19000pd tow and 6000pd cargo capacity
. I am paying more attention to the commercial non commercial laws and the need to have a health cert after June 1 the same as a truck driver.