I can recommend the Flysimware MU-2. It has great depth to all its systems and you can choose from three avionics layouts, including among others, Reality XP Weather Radar integration.
The VC's 3d is highly detailed with all switches and systems working as in the real aircraft. The start-up and shut-down procedures for the Garrett TPE331-10 engines have also been faithfully modeled, including the start locks.
The MU-2 itself is also a unique and much more interesting aircraft than all the usual suspects such as King Airs that have been modeled to death by virtually every addon manufacturer.
If you're not familiar with this aircraft, the MU-2 was the first twin designed from the beginning as a turboprop. King Air's, Cessna C441's, Turbo Commanders etc. were all derived from piston engine aircraft.
With it's highly loaded wings, the MU-2 can cruise at 300 knots, yet its full span flaps allow it to have a low stall speed of 76 knots, which enables it to land on short unprepared airstrips.
The high wing loading has an added benefit of giving a very comfortable ride in turbulence. Be warned though, although the MU-2 is a very well designed and sturdily built aircraft, it needs to be flown with respect and by the book or it will bite back... this makes it even more fun to fly in FSX!
The real MU-2 needs to be flown more like a jet than a turboprop, with many procedures similar to that of a jet. This performance and its general flight characteristics is also one of the reasons why all Air Battle Management students at Tyndall AFB are required to complete eight sorties and 24 tactical intercepts in the MU-2 before they can move on to aircraft such as the F-15 and F-22.
Here's the MU-2:
http://flysimware.com/website/MU_2B_60.html
There are also a number of beautiful repaints made by Bernhard, which are available for download here on SOH...
http://www.sim-outhouse.com/sohforu...tsubishi-MU-2B-60-quot-JGSDF-51-9763-quot-zip
http://www.sim-outhouse.com/sohforu...tsubishi-MU-2B-60-quot-JASDF-93-5203-quot-zip
http://www.sim-outhouse.com/sohforu...tsubishi-MU-2B-60-quot-JASDF-93-5230-quot-zip
All repaint below by Bernhard: