Say 6k, doesn't need to be a minter mechanically but I would prefer if the running gear was sound.
I would only go for the best standard fitted bits from the impreza range (i.e cheap) in the best combination then map it front mount. A few whiteline bits to sort the handling, job done.
To be fair if its light track work then any Classic Impreza will do the job as long as you stay within the boundaries of the engine and gearbox, both are not great in Classic form. Having said that, the later('99-0n) TY54 gearbox's in the STI's/RA's and Type R's have a hardened gearset and do tend to take abuse better than the earlier TY52 gearbox's but they are still not in the same league as a Newage STI 6speed.
The 2.0 engines in the Classics have a weak point, the rods! The stud/nut combo is the bug bear which in turn really makes no Classic engine stronger than other in standard form whether that be WRX/STI or UK, all though the STI does come with Subaru forged pistons but they are nothing like aftermarket forged pistons. The real bonus with the STI engine is in the form of the heads/cams, solid lifters and wilder cams with a higher rev limit, really necessary for any big build or another route is the AVCS heads once again from the Newage STI.
People talk about the closed deck block engine being a strong engine, that's not entirely true, the strength lies in the block itself not what's inside. A CBD only becomes beneficial when running high boost due to more material around the cylinders(less cylinder wall flexing) So with anything under 500bhp an open deck block will more than suffice.
If you really want to start with a good track base car to keep to modest to power levels than a DCCD equipped car is the one to opt for.....An STI RA or an STI Type R as mentioned in the thread.....These two models(behind the 22B) are the best Classic models to leave FHI's factory but come at a price, good ones are very sought after. With the DCCD run in open diff if gives a front/rear wheel bias of roughly 40/60 with none of this legendary understeer the Impreza is known for.
There is so much Impreza info, i could go on all night...lol...If you any have questions fella, fire away and ill try and answer.....There is one thing, Classic Impreza track cars are not cheap hence why after 12+ years with Imprezas i opted for a Clio Cup, i can continue doing something i like at a fraction of the price!