Sam Suwanasung was one of the city's first apostles of Thai cuisine, and he has hung out for so long in a undistinguished strip center off San Pedro that we tend to forget about him. Now, in the equivalent of a culinary midlife crisis, Sam has reinvented himself by pulling up stakes and moving downtown to new digs in the Riverwalk Plaza Hotel across from the Bexar County Courthouse. The move was something of a stealth operation, with the old occupant out and the new one in, all very hush-hush, in the matter of a few days. Such was the stealth, in fact, that few know he is there yet. That is bound to change. The pretty good buffet for $7.99 will draw some for lunch to be sure; the courthouse crowd lost no time in figuring that out. And the special plates are generous to a fault - another plus. But lunch specials are rarely any Asian restaurant's best food forward, and Thai Kitchen doesn't radically alter that equation. - Ron Bechtol