So far, the only ship upgrades are to the +ships sold in FM, and a few upgrades for ships sold at AI bases, like Wingship -> Wingship II and Bulk Trader to Bulk Trader II. I figure we can start with these and see how they go, then decide later on how exactly to change the old ship BP's that make +ships to make the upgrades instead.

Worked fine on a couple of old Wing IVs I tried it on.

Did you ever get around to putting in a new graphic for the Wing IV+? The ones I upgraded still use the same old graphic.