I just bought the DC. It looks great, and the car feels slightly stronger. I had heard the Comptech and didn't think it was loud enough, so I got the DC. Unfortunatly for me, the DC is not very loud either, in fact I think it is quieter than the Comptech I heard, that's why mine is in for sale section. My advice, if you are looking for the power without being really loud it's a great choice, but if you are like me (looking to be heard from a block away) I'd look elswhere. It just depends what you are looking to do.
Aaron