Bro,
3 hours is very tight. To many variables which will get you screwed. Flight delay, check in suddenly long queue, transfer journey either to or fro kenna jam, escort arrives later etc. etc.
With 'certain' pass you exit through VIP counter in BKK but join local queue in DMK. This is pretty fast and deterministic. Re-entry with the security checking wil be a bit longer. Forget about downtown hotel. Maybe can consider those hotels along Lat Krabang. I do believe any hotel that provides massage should meet your 'requirements'. I do not think there will ever be massage shop within any airport that will meet your 'special needs'. Why not try to 'discover' yourself and google those Lat Krabang hotel.
