Do a quick search and you'll find my .02$ on the matter.
Long story short, I had a wavetrac installed at VAC. Ran into some problems with it and after a through diagnosis, discovered it was a manufacture defect. They are actually more common than you'd think on wavetracs. Search for clunking wavetrac and you'll see what I mean.
VAC replaced the unit with a Quaife under warranty. I just paid the difference in cost between the two units. Overall excellent customer service experience.
Stick with VAC. You won't go wrong.