sure... Where do you plan on putting the extra cylinders
The only Pintara capable of fitting an RB26 is the R31 (Rear wheel drive one) because that engine bay was designed with the RB series engines in mind (RB20ET Passage GT in Japan, and RB30E skyline)
For a front wheel drive setup you need to fit all 6 cylinders, a gearbox/transaxle/diff and driveshafts ACROSS the front of the car, not along the centre, like in a RWD setup.
Of course you could mount the engine in the boot, reverse the spinning of the tail shaft and make it a Rear engine, Front Wheel drive.
You won't see much change from your 20 grand though.