I think it's safe to say it's certainly an issue, especially on cars before 06 when Porsche went to their giant bearing for the IMS. However, it is remediable with the fitment of an aftermarket bearing.
As to comparing a Boxster to an SC, they are totally different cars. The SC's are known to be bullet proof, and have all the charm (take that in both positive and negative light) of the older air cooled cars. The Boxster is a modern car, complete with it's high and low points.
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Boxster S
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