2006 Yaris head gasket replacement?

[jzr756]

Hello All

Just wanted to ask if any one has had long term success after replacing a head gasket on a 2006 Yaris as the thermostat froze in the closed position and severely overheated the engine
The reason I ask is I was told by a toyota repair shop that they do not do head gasket replacements on the Yaris engine I vaguely remember hearing due to a poor long term success rate with this repair.
Also, not really sure who to go to for a precision cyl. head resurfacing job as it's been years since I've indulged in this sort of thing and most machine shops back then mostly worked on domestic iron.
So I have a few questions.
#1) do most just go ahead and get a replacement engine from one of these import engine suppliers? prices seem to range between 600.00 and 800.00 around here.
#2 Is using an after market head gasket as good if not better than an OEM gasket?
#3) Do these engines use torque to yield head bolts or can the old ones be reused?
#4) and finally since the engine block is also aluminum do they ever warp just like the cylinder head? Any and all comments are greatly appreciated.
The car is a daily driver and runs perfectly but coolant needs topping off every couple days

[ex-x-fire]

I'd go used engine, some good yards will give you a warranty for them.
#2 yes, most shops use aftermarket gaskets.
#3 yes, most engines since the 90s have those head bolts.
#4 most shops have the head only machined flat.