Steve..... I've had this car for 7 years.
Option 1: buy a second hand m35 turbo and fit it. you may get out if it for a about $1,200 but the turbo could last either 2 minutes or 2 years....i can garentee it will fail.
Option 2: rebuild your current one and it will probably last longer than the rest if the car. i've already supplied you the price!
There is one other option. I can supply a hks kit with external waist gate for $3,500 not including fitting.
Mate this particular forum or m35info has more info on it than probably any other part of the world.....
Enough said!