well i would reccomend getting an exhaust and maybe a jet kit personally i prefer being loud espically in south florida where theres alot of senior citizens that beleive they are god when driving. if your just trying to turn heads tho there are many options such as neon lights, alarm/remote starters/blue xenon headlights/ but hey if its a true midlife crisis you could strap wings on it and install a 5000 hp concord jet engine on it check out the guys at:
http://www.katanaplanet.com/kp/forumdisplay.php?f=2
they usually have some good ideas for katanas
http://www.katanaplanet.com/kp/forumdisplay.php?f=2
they usually have some good ideas for katanas