I used to have one of those warrenty things on my old car. You read the fine terms and it doesnt cover shit, and you have to take the car to places that the warrenty people deal with, not who you want to deal with.
I think a reliable decent mechanic that you can trust is alot better then a dodgy warrenty. Find someone you like at a workshop that looks after skylines and you wont have to put up with this shit. The warrenty doesnt work out to saving you much money after you spent it on this so called service by these goons. Get everything done right the first time