[MrForbes]

IFI tractions were rubbish in 2006, but they redesigned them for 2007 and the new design is great....no more screws falling out.

And not all teams have access to CNC equipment.

Spending $50 each for traction wheels may be a good idea if you have the $50 per wheel available to spend....or maybe not such a good idea if you're really pressed for money, and need to use it for other things. We can't make that decision for you.