Right now I'm requesting an intermediate with navigation, manual transmission ok. Any ideas what I will get or should I request a full if an EU intermediate might pop me into a Smart Car ??

I flew into BRU quite a few times back in 2005 and I always booked a "B" car (I guess that would a Compact, right?). Their selection in that class is not real good, but at least I never got put into Smarts... Lots of Opel Astras, and I drove a Ford Focus C Max MPV way too many times. I also drove an A-Class Mercedes, which will forever rank as a completely forgettable experience.
After I made Presidents' Circle, they started bumping me to "C" class, which I believe is the equivalent to Intermediate. I got many Ford Mondeo and Opel Vectra vehicles, in various configurations (the station wagon being the more common). I know they have several Renaults, Volvos, and Mercedes Benzes, but I never got anything remotely interesting. Serviceable, yes. Interesting, no. YMMV....