No, it won't be safe to mod it- at least not if you plan on driving it for very long. Keep in mind there are a ton of other maintainence items that usually go along with a high mileage car, like suspension and drivetrain. These cars will last well into the 300K mile range, but not if they are beat on and driven like it's stolen.

 

No, the 3071r is a full frame turbo that would need a t3 flanged exhaust manifold and a different downpipe or cat that was flanged to meet the turbine housing outlet. You will need quite a bit more than just the turbo, tune, dv, and downpipe. Your talking a sizable Intercooler, clutch/fw, injectors, bigger maf housing, exhaust, fuel pump upgrade, a wastegate unless you buy an internally gated turbo, oil and coolant lines, an adjustable fuel pressure regulator, etc etc.
Theres alot to it really, and you can make alot more than 275whp and will want to look into doing your rods at a minimum, depending on power goal.
A much simpler way to do it which wont require nearly as much aftermarket parts would be to get an eliminator type turbo. These are a bolt on and go type, that can make around 300awhp and dont require nearly as much supporting mods. A decent front mount, clutch, and exhaust are pretty much all you need to run these setups. Pretty much everything else will come in the kit.
RingerRacing.com is your best friend.

 

Yep... talk to Mike, and that VR4 is toast...