[blau911]

A running 911 engine is not necessarily a clean bill of health. Just like the cost of an engine rebuild can vary greatly between a top end valve job for $4-5k, and increasing to $15k when the rebuild requires the case halves to be split, and have the magnesium case line bored (which most of them need due to warping after many heat cycles), new P&C's, cams resurfaced, etc. and that's just the engine. Then there is the fuel injection system which may need to be overhauled. Rebuilt pumps cost a few thousand, then there are new injectors, intake manifolds and butterflies, etc . Overhauling the mfi by itself could cost $5k or more. Imagine buying a "running" engine for $12k as a few here have priced this engine, only to find out it needs another $15-20k. For $30k you can buy a nice rebuilt S motor from a reliable shop.
If this engine actually has good compression and leakdown numbers, doesn't leak oil, and idles and accelerates well with no popping, no flat spots, etc, then the engine is worth I'd guess $10-12k. Thats a best case scenario. The 2.0 E engine only put out 140hp(same as the 2,4T, but the 2,4 puts out much more torque). It's not a fire breather. Just a nice little engine for a small light weight car.
But People in the market for a replacement engine who are not concerned about a matching numbers or correct numbered engine for their early cars, are going to be looking for a 2.4-2.7 higher performance engine, not a 2.0E. If I were in the market, a 2.0E engine is not the engine I would be necessarily looking for. Just my 0.02.