Never had any issues with the Roush kit, and I'm at 11, 600 miles on it now.
The only issue I have encountered is the weak link of the factory oem tensioner
pulley as it's already failed on me afew weeks ago. But besides that
I would say both Whipple and Roush kits are pretty proven at the
moment, I know Whipple had an issue with longtube headers and tuning
at the beginning when I was already running a setup with my Roush
kit but I think that's all been resolved and their up with the times.