It doesn't I have mine out and it has been in for service with the back seat out. Nothing was said and it is going back in to have to hood scoop replaced next week under warranty. So 'm going to go with no on the voiding of warranty.
I have to agree with previous posts..Your instructions and pictures are excellent. I deceided to check posts here before removing the rear seat and am glad I did...Thanks for the super instructions..and by the way, it does make the Works exhaust sound better !!!
What would possibly be more practical would be a single rear seat that's set at an angle to give some real leg room...these seats as they are are only good for toddlers or people with no legs. Thanks for the link though, very helpful!