Here is a modification I did to remove my center seat in my Nitro Z 8. I put in a wide step up to make it easier to get up on the back deck. I used composite deck board purchased from Lowe's for $40. I used grey deck screws to match the grey decking. If someone needs to sit in this position, I just use the throwable square cushion to sit on. The only reason I put the back board on was to hide the 3 holes that were for the bolt holes used to attach the old seat back. I thought about making this a storage box, but decided not to because then the step up was too high. Hope this helps someone, it was very easy to do.