Why not go for the Turbo model. If your importing I think its a bit of a compromise to aim low. There is still quite a few options on the Spec S.
These cars should hold their value well as drift fever takes hold as they are great drift cars and have many tuning options for them.
For the S15 Silvia, there is an "Aero" variant with a large rear wing. The Spec-R had a 6 speed box, uprated suspension stiffer body, 4-piston front brake calipers, brake power was increased also, it had the upgraded helical limited slip differential, and HICAS (High Capacity Active Steering) 4wheel steer as an option; wheras the Spec-S featured only the 5 speed box or 4 speed auto 2-piston front brake calipers, and the viscous limited slip diff.
Later on things got interesting when some special packages were introduced. Notably Autech offered some fantastic tuned versions. The second edition - "Style A" had been modelled loosley on a Ferrari. Going with higher compression the power output, and completely revised cams and ecu etc... power was raised to 200hp and this version also had the 6 speed box and some other features only found on the Spec-R.