Just a quick follow up.
RS-4 225/45 fit under the fenders of 2000 Civic with no issues. 41 mm offset on 7 in wide wheel. With and without 6mm spacers.
Also, these tires were shockingly good! I’ve been using purple crack SM7s and have not run a 200TW tire on this car before. While the Hankooks could not match the outright pace of (new) Hoosiers, they were very “drivable” and posted very consistent laps over 60 minutes. 10 of my 17 fast laps were within 0.6 secs.
All data is from Road Atlanta at 90+ degrees and stifling humidity. YMMV.
Someone will want to know, so, best ever lap at RdAtl 1:46.6. Best Hankook lap, 1:48.8 on the 19th lap.