I'd wait, but not until after the $2,000 crank kit offer expires. My understanding is there has not been a single failure on the Cranks that are covered under the SB. Is this true? SB's are not mandatory under part 91, but I'm sure not complying won't help resale either. I would be surprised if this is true to see an AD. SB's sometimes are a revenue generator and a way to limit libiality. I think the price for a crank "kit" is around $9,000 after Lycomings offer expires.

Lyc SB 566 covered 2500 engines and Lyc paid for everything including r&r and shipping. Lyc then wrote SB 569 and 569A covering another 5500 engines which they don't want to pay for. This is where they offer the $2000 deal up to Feb 21 2009. The SB was written Feb 21 2006.
Part 135 ops. will probably be up to tbo 2000hrs in this time as the engines concerned were from 1997 to 2002/3, an odd 2004 or two are also affected, so the engines will get opened up anyway. Pt 135 Lyc's must be overhauled at 10yrs for pt 135 anyway.
Part 91 ops. Some engines will be prop struck or opened for other reasons prior to Feb 21 2009, so it's only $2000 for those. The careful, no propstrike owners will have to decide whether to pay the teardown inspection cost of aprox $4 to 6000 before 2/2009 or keep on flying until the FAA AD note terminates the crank usage in 12yrs from 2/2006 as it now reads. Lyc says it will charge full price $10 to 16000.
FAA could change this and so could a lawsuite. Supposedly there have been no failures and some engines are into 2nd or more runs.
www.lycoming.textron.com click on Black front page and 2nd page has the bulletin links. Then call Lyc because even though your engine S/N is listed, some don't have the cranks. Double check this info, it's what I've gleaned so far and may have errors.
Jeremy
Jeremy