63 Dodge Dart newcomer questions/advice

Welcome! IMO I would keep it a Slant. I don't know your situation, nor your future, but I would bet down the road, if you decide you like working on cars, A V8 car will find you. Meanwhile, get your feet wet with getting the \ running & driving. Don't go overboard with trying to hop it up, just in case you do decide to make the change. An early A is a conversation starter, & so is a \6 in its own right.
I miss my old \ Dart, & after getting my current project done, would like to find another Slanty.