I recommend "Pang Shop" Suchat Kultipun 081-5951143 Thai Speaking only. Turn into Racha Uthit Rd off Chiangmai - Lampun Rd. Then Turn left into Soi 2. opposite the Gymkhana Golfclub. It is a Small Shop under the "Apichat Apartments" A bit difficult to find but worth it.
I had him rebuild the Back Shock on one of my Pantera's and also stiffened up the Front Forks on all 9 of them. I then took my Yamaha TTR there as it was getting pretty Soft and Floaty, he stiffened up the Front a little and Rebuilt the Back Shock on that as well. I was a bit worried as this has a Nitrogen Filled Remote Reservoir but he assured me he fills it with Nitrogen and the end Result was Great. Typical Thai Style shop, "Rough as Guts" crap everywhere but seems to get the Job done. Normally done in a Day. Good Luck.