Hi Stephen:
Without a doubt, your best route will be the Calibre35 M31/T2 conversion. It is very comprehensive and the fine details are nice (e.g. the cotter pins on the nuts are there!). The production (casting) is top notch too.
(Please note that I supplied some research material to the company and that my sample was gratis but nonetheless, it's very good.)
I had the Azimut kit and ebayed it when the Cal35 kit came. It's generally accurate but one of the hull boxes is too short and it's level of finesse isn't as nice as the Cal35 one.
I've seen the DES kit built up but it looks comparable to the Azimut kit, I'd say.
(I think
www.missionmodelsclearance.com has the Cal35 kit on sale right now)