No SR**VE motor was ever fitted in a factory rear wheel drive setup like the silvias. Mid 90's developments of rear wheel drive SR series engines had a form of variable timing control I believe...
SR**VE motors were fitted to Primeras, Wingroads, Lucino VZ-R and Pulsar VZ-R and came only in front wheel drive setup.
Engine management for a CG10 and CG13 are essentially the same so fitting an emanage to either will be no different.
If you try and turbocharge the vehicle on a tight budget it will probably go a-over-t on you which won't feel very good.