I've got a Roush 402SR in my car and encountered an
oil leak after 2K miles (leaking
oil galley plug). The installer (who is also a Roush dealer) is doing the warranty work and facilitated the warranty arrangements with Roush. The process to get authorization is a bit slow, but Roush hasn't balked at covering the parts (new clutch) and labor.
I know that it took Roush a LONG time to rebuild one the South Bay folk's 427s, but they came through in the end.