Welcome to the Legend family. The most active forum is at
www.acura-legend.com.
There are not that many off the shelf G1 Legend mods. Weapon R has an intake pipe for manual transmission cars (autos have a bracket in the way). Stromung offers a coupe exhuast. No headers available off the shelf. Word is Tokicko is discontinueing their shocks for the G1. I think lowering springs are still available.
The beauty of the Legend is its durability and high speed handling. Both the wife and I have Legends. Hers is stock (G1) and mine is modded (G2).
I would give the car a modest drop and slap on some rims. Anything else is personnel preference and wallet size.