IIRC, there is NO difference between the ATX and the MTX Duratec 2.5, they bolt up the same way in the Cougar. The only caveat would be if the MTX-75 in the 'Tiques had a different housing than the one in the Coug, and I don't think that is the case. I believe you're OK, but hopefully someone with more MTX knowledge will chime in as well.
