I've been slowly upgrading my rollingstock fleet with Full Throttle Z Scale Knuckles and new wheelsets from Fox Valley Models and BLMA. For those interested Will of Full Throttle (http://www.wdwfullthrottle.com/contact.htm) may still have some "naked talgos" (z scale talgo trucks with knuckles, less wheelsets) available. Anyways, the BLMA wheelsets track beautifully in addition to looking far better than stock wheelsets. The couplers are a bit stiff, so I'm going to attempt adding weight to see if that improves coupling.
The hopper is an MTL car with BLMA wheelsets and body mounted FT couplers. The car on the right still has it's stock Atlas wheelsets, but has received BLMA wheelsets. Just as a side note BLMA wheelsets are only suitable for MTL and Athearn cars. Atlas cars need Fox Valley wheelsets (still very nicely proportioned) due to the longer axle length.
(http://i222.photobucket.com/albums/dd264/Guilford_Guy/Model%20Stuff/IMG_0402.jpg)