If you haven't seen it yet, there are some tidbits on the Toyota Japanese site about the 86 that certainly pertains to the FR-S and BRZ.
Questions about the 86
Things like:
*GT Limited & GT trims [i.e. USDM] = 215/45R17 87W, 17 × 7J aluminum 5x100, offset= +48, hub bore = 56mm, bolt hole = 14.5mm
*Loudspeaker specs:
Dash tweeters are 1", 2.5W rated, 35W max
Door woofers are 6.3", 20W rated, 40W max
Rear panel speakers are 2.5", 10W rated, 35W max
[doesn't mention the assumed two midranges in the dash we get in the USDM car]
*Lighting:
Halogen low beams are H11, high beams H3B
HID bulbs are D4S
Taillights are 12 LED's per side
*Glass
Windshield passes 79% visible light, blocks 99% UV
Side windows pass 73% visible, blocks 91% UV
There's "green" and "privacy" rear glass, not sure which the USDM gets
*Interior dimensions!
Depth of trunk with rear seats up is 810mm at bottom, 670mm at top
Height of trunk is 340mm min, 390mm max
Max width of trunk is 1395mm, and 1075mm between wheel arches
...also dims with rear seats folded and front seats full-rearward
1435mm from bottom rear of trunk to back of front seats, and 1250mm from top of trunk to upper back of front seats
Enjoy!