OK, your core components for the Stage 2 are: side exhaust, floor mats, rear wing, wheels and tires, Roush suspension, front fascia, rear valence, Roush emblems, window badging, trunk toolbox, side shirts.
Options on the Strage 2 are: styling bar, subframe connectors, pedals, wheels and tires, leather seats, performance breaks.
It looks like the only mod that would add HP to the car is the side exhaust and I'd say that would maybe 5hp since the catback really isn't a restriction, so we'll say you have 265.
It looks like you car was made to shine in the twisties though and depending if you have the optional equipment it can probably hold its own on a road course.
You can find everything you need to know at
www.roushperf.com
------------------
1997 Thunderbird 4.6L: Black w/ grey leather Ram Air w/ K&N, FMS U/D pulleys, FMS 9mm wires, Dynomax exhaust. Soon: custom burned "Inject tech" chip, trans-go shift kit, 28,000GVW trans-cooler
No Longer own: 91 LX 5.0L 5 spd Red w/ black interior
2 chamber flowmasters, Bassani off-road X-pipe, MAC cold air induction, Kirban short throw, Heavy duty 3 core radiator, FMS 3:73's, Timing bump to 14 degrees, SRP billet racing pedals, Kenwood sound system