Thanks all for the answers, I'll write how it has gone in case someone interested.

It took 2 trips to immigration office to make them transfer my stamp, copies of every single page of my old passport, 1 trip to atm to withdraw 20k, fake air ticket, proof of address, wasted all morning just to get stamped out of Thailand.

Then the boat is 100-200 one way, stamp service in Myanmar 500.

Wanted to try once but I won't repeat and I'd advise against this option.

@Rob *******

thanks for the report, doesn't really sound like something I want to do, I'll think about it

@Brandon ***********

you mean they had less than 2 entries and still had problems?

@Stuart ********

40 minutes quite a long ride, is there a ferry or anything like that? Can you show me on maps where to take the boat?

@Brandon ***********

I have a multi entry visa

Never had a fine for 1 day overstay

Multi entry and never visit an immigration office again

Maybe that was enough to queue at immigration before the rest of the plane and saved 2 hours

@Mark ********

normal full page sticker?

@Julie *****

all good, I'm on 1 year multi entry now, I just have to travel out every 3 months, which I'd do anyway. No more visits at immigration office or hassles whatsoever