wow... what a long post hahaa
if it's an 86 1/2 then it is a mk3 model... i would assume two things..
1. you don't reside in the USA
or
2. you got an original ma70 that was non turbo and someone has swapped the turbo motor in
i would say $3500 would be fair for a good condition one even up to 4 if you think she's really a beaut but yea.. play the "screwed turbo" and oil leak game and you should knock him down a bit
don't forget when you do the metal head gasket and arp head studs to prep the head and block to the lowest RA you can... mine is being done to 17RA, your reconditioner will know what this is... if he doesn't.. go somewhere else lol
my mk3 with upgraded ct26 (46 trim), 500x300x75mm intercooler, 2 1/2" hardpipes, 9psi, 3" exhaust from turbo elbow back with stock fuel system managed a 13.6 on the 1/4 mile
consistantly i might add
there is a fuel cut off, the 7mgte works on flow rather than psi
map sensor cars cut at whatever psi the manufacturer has set it to
the 7mgte is usually about 11-13psi sorta... if there is too much air the car cuts
there are a few options for solving this
a hks fuel cut defender (even tho i run one.. i would not recommend it) the only way you could run one of these is if you do your mods, install the fcd, cruise (DON'T BOOST) over to a dyno shop and ensure that you have the fueling necessary for your mods, once you have dyno'd and confirmed the fuel side is ok DO NOT ALTER ANYTHING, if you do, you may end up destroying something
other thing you could try... the lexus afm + 550cc injectors
the lexus afm housing is 25% larger than stock so allows 25% more unmetered air into the system which therefore you need to accompany 25% more air with 25% more fuel hence the 550cc injectors
basically you don't have to do too much to play with the srt hehe
exhaust, intake, 3" replacement elbow, upgraded ct26, 10psi, upgraded intercooler hardpipes, intercooler and you'll be rearing to go