Well depending on the car you get, the costs can vary greatly. The turbo on my CA 180 is only worth about $25
, but as you get better (and newer) they get more costly - S15 T28's for example regularly go for $800 upwards (second hand).
As for servicing - it depends where you take it. Most wont touch the snail, but then again from what I hear a lot of the members service their own cars anyway.
Then comes fuel. CA18's being older engines are naturally a little more hydrocarbon-hungy. With the stock exhaust and airbox you could be getting as little as 350km to a tank (55L). With my auto
I was getting ~300 for a while - until I turned hold mode off.. but that's beside the point.
SR20's however will cost you more up front but will get 400+km to a tank (correct me if I'm wrong guys) with stock exhaust and airbox.
As for parts, they can be sourced reasonably cheaply - given the popularity of the silvia
For example, a complete CA18DET can be picked up fro about $1000 and an SR20DET for about $2000.
The conclusion: Driven sensibly, there's no reason why a turbo 180 or S13 can't be a great, reasonably priced car, easily upgradable and with the added bonus of at least one brilliant site for like-minded individuals to come together and discuss these fine automobiles - and give certain members crap for having auto's
Driven more agressively, they can be a HELL OF A LOT OF FUN
Just make sure you do it on the track