I would recommend using either the RUU or a ROM. Or, the RUU and then a
ROM, if you like.

Using the RUU will update HBOOT to .92, the latest version. Going
straight to a ROM won’t. Updating HBOOT isn’t really that big of a deal,
but if you want *everything* updated, that’s your best bet.

However, if you don’t care, the ROM is a much more straight-forward way
to go.

In either case, you’ll end up wiping your phone (RUU does this for you,
and I definitely recommend doing it for any ROM), and end up with the
same antenna and software.