A tough call.
The Castrol is neat/cool, but it would be very close to the black, former Rogue/Cuffy Crabb, now Adam Corolla Grp2 racer that you might encounter on the grid in the future. Black and or Wht E9 racers are prevalent and the grid gets a little boring when everyone shows up with the same paint/livery, IMHO. I am sure event organizers like a little variety when it comes to curating a big 'show'.
Haven't seen a UFO tribute on the West coast, maybe elsewhere but what do I know. The E9 racers out there currently are wht or blk that I've seen (except for my brother's old Schnitnzer silver/red schemed racer) The UFO scheme sure does Pop on the track, hence the design I'm sure. Since your car is the 'real' UFO, it will trump any tribute when encountered.
Once upon a time way out West, the IMSA 'TBL' (wht), Mr. Crabb and his Grp2 (Blk) and my bro's Schnitzer (Silver/red) tribute all met at Buttonwillow at 'high noon'......t'was a fun weekend ;-)
http://e9coupe.com/forum/showthread.php?t=3231
Is your car the same Luigi that was at ZAP in England is it? I always liked Luigi yellow livery too.
Take your time (if you have it) and have fun with it, variety is the spice of life.