OK! so yeah, craigslist found me a sweet new (old) bike! a perfect condition '85 60cm Gitane Victoire, supposedly less than twenty miles on it in thirty years, all original except the tires and brake cables (housing is still original yellow). I've done some research and i'm aware that this was Gitane's entry-level racer. so component wise they stayed away from the top shelf, while still being functional and light. I found a components list for the full 85/86 line http://www.gitaneusa.com/images/catalog/1985_pg5.jpg my qui-shone for yous guys is this: what should my priorities be as I upgrade this french lilac?
first of all obviously is this ridiculous plastic seat-post. other than that i'm not quite sure where to go next.

things to keep in mind: 26, 6'3" 215lbs (and dropping), I wanna make this thing go fast, it's my first "real" bike in a long time but I'm lookin to get sweaty. so I want it to hold up, but I don't want to necessarily jeopardize it's "classic-ness" keeping it stock seems stupid considering I want to actually ride it to hell. but my priorities are thus: Durability, affordability, brand-loyalty-ability, period-correct-ability in that order.

pics to come (i don't have a camera, i'm trying to get the seller to email me the shots from the ad)