Morgan build the cars and owners finish them.
There are several after-market specialists ....
Mulfab,Librands,Wolf,SSL being main contributors.
Some dealers also offer upgrades.
Peter Mulberry designed upgrades that MMC copied.
Individuals have also done significant upgrades.
cearelsurfer and Monty recently.
Rog has contributed with some excellent parts.
DaveW has writtenbooks.
Others contribute to queries.
Development is often expensive. Also be aware of insurance issues as mods canlead to premium increases or even refusal.