have you got a spare $2000 lying around... with that you can get a metal head gasket, arp head studs and get your block and head done at a reconditioners and probly built for you so basically you end up with a new engine that can handle 400 rear wheel horsepower and you'll never blow your head gasket again... once built they are very reliable
for the non turbo, they can still blow head gaskets also... + after a year or so you're gonna wish you bought the turbo hehe... but for a runaround good reliable one get the non turbo, you can always do the turbo swap later on
really depends on your pocket and what you really want
the turbo one will need work straight away and it's not gonna go for a while
the non turbo you can drive straight away and enjoy the supras luxury
at the end of the day its up to you
let us know what you ended up getting... ring your local machine shop and see how much they'll quote you for doing a full rebuild etc, research then take action
good luck