Lets say you were shopping for a bike that had a remote start alarm on it with rear seat pop. How much extra would you be willing to spend on the bike if anything. Just for reference the system with install is valued at over $800

 

I would not pay more than you think the bike is worth. After market stuff only makes one bike potentially more desirable than another of the same make & condition. Not everyone wants Sat Nav. with expresso machine (although I sure would)
Wot it comes down to, do you think it's worth the extra $$$. Besides it all comes down to your negotiation skills anyway.