I have a Mr2 Rev 3 Turbo. I'll answer your questions best I can;
Q: What's the Mr2 like on fuel (both turbo and N/a)
A: Turbo's need to ideally be run on V-power and I get roughly 200miles to a tank town driving. Approx £65 to fill up.
Q: Any thing I should look out for when looking at them? (Rust, common problems etc?)
A: Check the sills. Rust is common on them and if bad they usually need cutting out and new ones welded in. Check it's not loosing any water. The waterpipes that carry coolant from the rear to the Rad are prone to cracking which causes coolant loss and eventually overheating. It's a bitch of a job to repair hence why they are dubbed "Hoses from hell".
Q: Interference or non-Interference, that is the question?
A: Assuming you mean if the timing belt snaps? The 3SGTE engine is a non-interference engine.
Q: Anything else you think would be helpful
A: If you get a MR2 get a turbo and get Rev 3 and onwards. Rev 1's and 2's have less power standard and the headgaskets are prone to going due to the fact they used paper gaskets. Rev 3+ uses a metal gasket. It also comes with LSD as standard. It has a different turbo too, although it has a ceramic shaft which has been known to shatter when boost is upped too much. They run 0.8 standard but can be upped to 1.1 bar with a MBC/EBC. 300bhp isn't too hard to achieve. The usual breathing mods and upped boost will see you on the brink of 300bhp with a healthy engine.
i also have a mr2 turbo but mines a rev2 tubby running 250 bhp at 11.5 psi with a decat, induction kit,RSR exhaust, greddy clutch, oil breather
first question, second question is more or less spot on but i get more mpg as i do alot more motorway driving...
third is also correct but i have known other mr2 turbo members engine to fail when the timingbelt snapped so its really a hit or miss with that one..
question 4 yes rev 3+ is they way forward. they are much more easier to modify and the turbo on them holds the boost better.. the only way you risk damaging the headgasket on a rev 1 or 2 is by running 1 bar (14.5 psi) for a long period, but they handle 13 psi all day.. rev 3 onwards all have LSD gearbox's but some rev2's also have LSD (like mine).. All mr2 turbos use the same intercooler and all mr2 turbos run a little rich too.. they can be a little tricky in the rain and snow so take it easy on your first few drives in rain and snow
ooo ye MR2 Turbos get better mpg than the N.A off boost but its so difficult to drive them off boost you get the urge to plant your foot down