Just wanted to share this update on my 280GE with a transplanted '85 "Euro" 280SEL (M110.987, higher compression) long-block (see earlier post for background). I am just tickled at its performance so far, and had to shout it.

I just took a 560 mile round-trip to Cambridge (MA) -- bringing home my daughter for Spring Break -- that included some hilly portions of the Merrit and Wilbur Cross parkways (CT) and Rts 91, 84 and 90 (CT and MA). Although I wasn't towing my boat, it was still a good test, as I have driven these portions about a dozen times so far in the past two years and I knew exactly how my G had previously performed on each of the particularly steep hills (e.g., the notorious westbound hill just after the tunnel on the Wilbur Cross near New Haven) along this route.
On these "stress tests", the G was fantastic. In the past, a shift down to third, running at around 4,500 rpm (cars travel quite briskly on these roads), was necessary to climb these hills without an annoyingly steady slowing of road speed (and pulling over to the right to let everyone pass). In stark contrast, I can now climb every hill at ~3,000 rpm and even continue to accelerate, even up to 4,000 rpm (about 75 mph) -- in only one instance, for a few hundred yards, a slight ping was heard (I do have about 9.25:1 compression ratio now) and I eased off the gas pedal a bit.
Likewise, not only on this trip but also on highways in my home area, I have found that the G is significantly more powerful. On many hills where, with my old engine, I had to floor it to keep up road speed, I now find myself driving up with only a slight extra push, if at all, on the pedal -- in fact, there are some hills that I've lost notice of.
And both my wife and I have realized that I'm not downshifting to third while I drive around the area on local roads -- previously, I continued to shift down to compensate for hills on secondary roads, whereas now I'm just keeping it in "4th" and just giving it a little more "gas" at times, something that was inadequate prior to the engine swap.
Fuel mileage, BTW, on the aforementioned trip (which included some 75 mph, or ~4,000 rpm, stretches just to keep up the traffic flow) was about the same -- ~14 mpg. And speaking of 4,000 rpm stretches, I also found that I had a lot more residual speed available, as I reached nearly 85 at one point and still felt that I could go faster. And, oil consumption was nil for that whole trip.
[all speeds, BTW, were determined by my GPS, a Garmin StreetPilot, as my speedometer is a little off).

Final determination of my degree of satisfaction (per the cost) will come a little later, when I start towing my boat around (by which time I will have "broken in" the engine a little more, too).

Right now, though, I've got a big grin on my face -- even though my wife, I think, is still going to keep the pressure up to get me to trade up for a W463 just for the "creature comforts" (if I do, I'll hold out for at least an M104 engine, rather than the earlier M103s -- once you've tasted the horsepower, you can't go back :-).