How old are the boys that you are building these for?
Who's gonna get the 2nd truck you build? Lol......
Or are you upgrading both at the same time?
I'm sure they will be very excited. And having the upgrades from the very beginning will be awesome. It just wouldnt be the same if you beat on these trucks for 6 months and then did all the up's.
Like 80% of us generally do, building as we break or upgrading as we go.