while I will generally agree with your take on this, I think it depends more on the type and amount of the modifications as well as who you talk to, and each case
must be investigated individually, the "MODIFIED IN ANY WAY, beyond what the manufacturer stipulated originally" applies more strictly to newer models
the rules actually state "All are admissible, provided they have not been substantially modified (see notes)" and the notes state: "Importer must be able to provide proof that
the vehicle is fifteen (15) years old or older as determined by the month and year of manufacture" .... if the particular official wants to say that means any modifications must be 15 years old or more, that's their interpretation, maybe just means being able to prove all the parts were manufactured before 1998, like an old carburated 350
new modern upholstery is not a "substantial modification", nor is a newer engine specifically - in most cases, any engine modification must comply with emissions regulations current in it's year, and in some cases [BC], if the engine is much newer than 15 years old they want it to be up to the most current regulations .... brake, steering, and frame/suspension mods is where the major problems are, and it all generally has to do with current federal vehicle safety regs
here's an entertaining bit on importing a vintage vehicle into Canada - bottom line is do your investigating well for your individual situation
Bill
