After reading, re-reading and getting my half dead brain to comrehend this whole topic, I have to say that I agree with Oz also, chassis is the main identifyable point on these vehicles, change the chassis, change the I.D. its a bit like changing your name and I.D. you may have been born "John Smith" but after changing your name so "John Jones" effectively John Smith ceases to exist you may look the same and have your original DNA that you were born with, but as you now go by John Jones=thats how you are indentifed.

Have I got this right???