I also think you would be wise to wait and let your third plane be a kit. I will second the advice someone else already gave: Get an Avistar for you second plane, then bash it a little if you want. Increase the control throws to give it crazy roll rate, take the dihedral out of the wing, make larger rudder and elevators from scratch, turn it into a tail dragger etc. etc. etc. In any event, after you become skilled with the Avistar, you can probably handle a kit like the Uproar.

Uproar is a very inexpensive and easy kit to build, I highly recommend it for your first kit build, But as for actually flying it, it's a very responsive plane and even on low rates will roll a little too fast to be a good second plane. Transitioning from an Apprentice to an Uproar will be a stretch for your skills and the plane will likely turn into balsa splinters quickly. But I think transitioning from an Avistar to an Uproar would be no problem.