Aviation Enterprises Annual - Required Install of Rear Access Panel?

[pwolfehagen]

Hello to all,
I have been lurking for a year and really appreciate all the info on this forum.

Aviation Enterprises will be doing a pre-buy inspection next week on a 1969 T337D that I have made an offer on. The aircraft is out of annual but if things look good the plan is to ferry it back to their shop in TN to perform the annual. Aviation Enterprises is requiring install of the rear engine access panel ($6990) as part of the annual.
I'd love to hear any thoughts and/or experience others have had with this install and how it pertains to future maintenance.

Thanks,
Paul