To me the biggie is the motor. Built 12 years ago and never really used.. does it run? is it seized up?
PCA classes.. GT classes have changed.. lb/hp being key, not just engine displacement.. so even if the motor does run fine, it may not be competitive as mentioned above.
Dulles international shop was a reputable shop in the DC area, about 10 years ago iirc. They have since closed shop.
Somethings will need attention and that crossed my mind:
1) Seats are likely out of date
2) Harnesses too.
3) Roll bar padding
4) Brake lines/pads and maybe even rotors could need a rebuild. - any specifics for calipers/rotors?
5) Fuel lines.. not sure I'd race with 10y/o lines
6) Carbs - if sitting with old gas they may need a rebuild
7) Any suspension specifics? RSR style? Spring rates , Shock type/brand etc? (which could also lead to rebuild needs)
of course, to "build" a car like this is a $50K proposition.
How "rust free" is the tub?
You might check out
www.dorkiphus.net - local NOVA/DC board.. some folks may even know the car/history etc (that could be a plus or minus I guess

) Lots of "aircooled" fans there.
Trailexes never go out of style. I would guess by age surge brakes. Can always adda tire rack/storage bins. I would guess $2500 for the trailer.