I always wondered if you could turn Thailand er, 'agressive'... and in such a scenario, radical anticommunist power figures may go.. tense. And get ready for war at least, as laos is close both geographically AND culturally...
It's a bad idea.
To be aggressive means a high defense budget.
As a developing country, that would mean to sacrifice your own economic development .
Especially when your opponent possesses a socialist command economy (a Titoist VN not a Stalinist one, but still...)
An underdeveloped economy create breeding bed for communist insurgencies (already was in OTL), in the same time, communist China and Vietnam may be feel threatened about your aggressive behavior and fund the insurgents. (Titoist VN may not get long with PRC, but when facing a common threat?)
Don't forget Thailand is a multi-ethnic nation, an shortcoming your insurgents can easily exploit.
Perfect scenario to destroy a country.