Evonation - I know this is not the information you were asking about, but it is more information concerning the engine family...

This engine weighs just 330 pounds. Its low weight was achieved through extensive use of lightweight materials: an aluminum block, cylinder heads and pistons, silicon aluminum cylinder liners, magnesium valve covers, and an aluminum oil pan. This unusual combination of plentiful power and low emissions is attributable to a number of unusual engineering elements: single overhead camshafts, rather than dual, reducing reciprocating mass and weight; three valves per cylinder (two intake, one exhaust), rather than four, enhancing catalytic converter light-off; two spark plugs per cylinder, capable of slightly staggered firing, to optimize combustion; one ignition coil per plug, to optimize the spark. Its 90-degree V6 layout rather than the more common 60-degree design allows Mercedes to create V8s using the same basic tooling, which should lower the overall cost of producing a line of engines. The result is a family of advanced new engines that will be used throughout the Mercedes model line and will take the company well into the next century.

Mercedes 430 4.3 V8 (same engine family as the V6) may be the key to up grading a Crossfire... the V8, by the way the information reads, would hook right up to the transmission in the Crossfire as is.