My 'back of an envelope' concept for a Mobile Gun System based on Boxer. This has a reduced-height hull with a 120 mm smoothbore gun turret. 3 Crew. Autoloader with 14 ready rounds plus 16 stored in hull. Very high levels of frontal protection. All-up weight below 40 tonnes. 
I'm going to stick my neck out & say this is what I believe a future MBT should be conceptually. Should be able to take-on T-90 & survive a frontal hit from one. Doesn't rely on tank transporters to deploy. Uses standard 120 mm NATO ammo. Japanese Type-16 MCV is proof of concept.
It would use a redesigned Boxer chassis in much the same way that the UK's Saladin and Saracen armoured cars used two versions of a common driveline. You would take the existing Boxer hull and reverse it for the MGS variant. Overall parts commonality would be at least 60%.
