I concur with the praise of the Denon 103 and 103R, and nobody has heard it properly until they've heard it in an arm that can manage it properly. That said, I'm a bit surprised that the Tri-Planar is one of those arms. I would have thought high-mass, preferably 12 inches.
I've run both carts in the extremely heavy Ikeda IT-407 (12") arm with superb results. Now I'm running the 103 in the EMT 997 (also 12") arm and it's even better.
The 103s also performed well in the 9" Ortofon RS-212, and would probably do well in any other real Ortofon arm (which are all vintage - the current Ortofon arms out of Japan are actually OEM Jelco and just mimic the look of original Ortofon arms) - you're talking RMG 297, 309, RMA 297, 309 and RF 297 and 309... or the Shindo Meursault if you've got the bucks.
Another route would be the original steel knife-edge bearing SME 3012.
