Well i take it this is your first bot ? I would suggest not starting with a spinner as they are hard to build well and extremelly dangerous and can only be ran at either Exterme Robots or RoboChallange FW Champs, get the drive chain and wedge going.

On a note about the design, to be honest don't see a benifit to the spinners location, it would still hit the heavy front armour of most bots in the same way a normal vert would, you are just adding more wedge for some else to hit. Also the wheel placement it would be hard to drive thanks to gyroscopics. To be honest even a extending saw would not help as it would just push the bot up and away from it.

Sorry if it sounds harsh but i would much perfer you to have effective bot as your first bot as it really helps you with confidence.