Hi, I don`t know anything about the promotive kit other than it uses a R1 motor, or is it two ?
Having briefly owned an r1 I can tell you after as little as 1000 miles the chain gets noisy due to stretch if used hard and that`s what they are for :) and after 3000 miles and the third back tyre its time to replace. You can double the mileage with sensible use and strict maintenance but I would guess the chain would be half the length and pulling twice the weight so its going to be a routine service part.
If you go down that route and the build uses the same 530 pitch chain try and buy a Regina chain as they stretch less than a DID and don`t go near an Iris chain or it will rattle within 600 miles. The sprockets will be fine as its just rapid chain stretch in a short time causing noise annoyance and I replace chains probably before I need to but iv`e had two let go in 30 odd years of biking and its not fun.
An R1 is fun over 100 mph and a burden below it which is why i don`t own one anymore and stick to sensible adventure trails bikes that help keep my licence and body parts.
Its embarrassing following a bus doing 20 mph up the town center when you`re revving the motor more than the kid on the scooter next to you as it has no low down pull coupled with the fact you have to knock it down four gears to over take slow moving vehicles below 50 mph and the amount of clutch slipping in traffic is a pain.
I would personally be looking at a car engine conversion for use on the public highway as the R1 would be a weekend short burst hooligan car of limited use.
..........Mmmmm Hooligan car..... ;)