Awesome car! I really like the day 2 or retro drag look or whatever you want to call it and I dream of having a car just like it someday!
As for the lettering...This might have been mentioned before but I believe you can get vinyl stickers that could be applied to look like they are painted on and they could be removed later and maybe not screw up the paint too much.
If it was mine I would probably add the letters if they could be removed someday.