I agree that the stock arm on the GAE is outstanding. I have not compared it with a Triplanar, but have an SME on another TT, and a VPI 3D w/dual pivot on another and compared to them it is easier to set up and sounds as good as or better than the others all things considered. In terms of headshells, I use the Zupreme and more recently have found the Yamamoto HS-4S carbon to be even better. Actually a lot better. Both have azimuth adjustment and weigh a reasonable 12 g or so. My favorite of several cartridges is an Ortofon Windfeld and my preferred phono preamp is a Conrad-Johnson TEA2MAX with a Bob's SUT.
SL1200GAE New Tonearm
Want to change the stock arm. Looking at a triplaner 9" vii any other one around $3500 new used . No preferences in particular.