how much do you want to spend and how much power do you want to make
a "t3 turbo" is like saying you have a "computer" for sale
there are million different pc manufacturers, combinations, models, variants, specs, speeds, etc, its impossible to clasify it as a "computer" much like a turbo as a "t3"
typically "t3" spec turbochargers are cheap ass-spec units either sold on ebay or from dinosaur spec cars like vl turbo's etc - probably the standard one is better and easier to fit
a no-spec'd t3 is worth no more than $300 ? it could be complete junk on your skyline?
a brand new ball bearing garrett spec is typically $2000, so a sub $300 is going to be shithouse
a 2nd hand R33 turbo is worth $200-$300 in comparison
get the turbocharger compression tested or your engine? you can't compression test a turbo, but you can get it inspected, checked and verify of specs and/or model etc
ATP in melbourne can do it for also some well known workshops can inspect them for you and do basics checks, but for true check i would check with ATP
ATP is the only place i know of, there would be heaps more in vic, some other guys will post up some places
if the turbo isn't bolt on, it isn't bolt on, period. highflowing it doesn't make it magically bolt on.
if the t3 turbo you still want, doesnt fit, then youll have to change stuff to make it fit. probably flanges, bolt patterns, spacers, rotate the housings etc to make it fit
highflowing the turbocharger involves a replacment of all items that are perishable (compressor wheel, exhaust wheel, bearings, seals) and the only things that remain original are the cast iron housings. the replacement items are higher flowing spec (thus the term highflow) so it makes more power for the same sized unit.