Oh I believe you. That's why I found it interesting that AMG itself reported the E55 was faster than the E60. I also found it interesting that, again AMG itself said the SL73 was only .2s faster than the SL600s. Both of those reports went against what I would have thought. It's not like there was a huge weight difference in the engines. If anything, for example, I'd expect the SL73 engine to be lighter than the SL600, due to the extra boring.
Interesting note, Dave, I bought "AMG 45, The Story, The Cars" largely as part of my research into the SL600 when I was contemplating one, because I wanted to see what was different from the unobtanium SL73. Nothing but the block. Nada, zilch, nothing. I discovered all sorts of interesting tidbits (like the W210 E50 and E60 have the SL600 rear brake systems). What MB and AMG were doing with the W124, W140, W210 and R129 chassis cars between 1992 and 1997 was nothing short of fascinating. It's the kind of Franken-test-engineering only a true HWA gearhead could appreciate. But as Klink pointed out, it was near death secret to me until that book.
maw