my personal opinion is build as per the ~"blue book" (not seen one my self as i don't do this kind of thing) as you will only test your design upside down into a wall
What he says!
When you come to sell the vehicle it's a bonus if it's to regs and can be used for competition. You may even decide to start competing yourself after a while, when the fun of just playing runs out. Be a right heartache to have to change something that's welded in then.