Good info, 280zforce...
I'll add that a 510 would be a screamer with just an RB25DE and some cams and mild port work + header too
...so perhaps you can get away with steering linkages being in a good spot by dropping the turbo idea, working the engine back some, making a shifter linkage adapter, which may need the shifter location hole to be cut around further forward and backwards, raised a couple of inches to allow a linkage, and then closed up to seal out the exhaust or whatever else may make it's way in there...
all that is done so that you don't end up having to move the seats further back either.
a 510 is a car I could see an RB20 in, even though it's not much shorter than its 2.5 or 2.6 brothers, the extra room, cost savings, and other such things you will avoid doing to the car to make things work will contribute to the money left over for engine mods to get you passed the standard RB26 horsepower level.
and really, anything like 300whp in a 510 is enough to have NASA call you and ask why you're gliding through U.S. Air-space on your way to the moon.