well that's a bit of a facepalm. :P My advice would be yeh sure make it for the sidewinder, but just incase you do upgrade make it a bit wider for the G27/25 cause they're only about 170gbp on amazon at the best of times. I've had the same thing in mind (praying that one of my parents cars fails its MOT so I can steal some bits out of it i.e. dash, drivers seat, seatbelt, carpets.
Should be fun aswell to see if this does go well if you could give some feedback on what was harder, IE mounting of dashboards/light wiring
Just an idea, see if the Finnish amazon/ebay has anything like little blue LED fans, put them in the cooling vents in the dashboard, and please ASAP upload some pictures and you may even encourage some of us to donate so you can put in a wicked sound system.
Oh and something else you might want to look at is wiring of switches when you do upgrade your wheel, taking it apart, and using the buttons on the wheel as switches for lights, horn, stuff like that.
Good luck and feel free to PM me if you have any issues.
UPDATE-MOT Passed (sadly) So going to the local pug scrappy and getting some bits and taking them back in the van and mounting to an arrangement of pallets+planks bolted together... should add pics+thread soon!