well, the short answer is yes, it is possible.
but with this radio being an SMT style radio, the likelyhood of a "home tech" being able to do it is not great.
i doubt you will find a set of instructions online for this reason.
just so you know, adding a second final to that radio and no amp will be less than 1/2 an S unit better than it would with a single final.
lots of work, lots of potential for damage, and not much noticeable gain afterwards= not worth it.
you could end up with a 500 dollar paperweight!
LC