It's highly recommended to go with better angle UCA's if you do a front level. I have the RC 1.5" front level, and the RC 3.5" UCA's installed at the same time.
I know there was at least one poster on this board who had his UCA snap (around the ball joint or the ball joint itself, if memory serves correct) while driving down the highway. I am 99% sure that person did not have better angle UCA's installed recalling the thread/posts. To me, if one is spending the $ on the front level, it only makes sense for safety reasons alone to also install better angle UCA's built for the front level kit.