Interesting. When I was experimenting the other day (purely for science of course), I swear my stock 1330 (2019 RTL) wouldn't budge over 4500rpm or 4800rpm in 6th gear, I cannot recall which it was. (Unless my memory is just completely short circuiting.) I was WOT for many minutes. I assumed that it was RPM limited, but I see the attached spec sheet for the 2015 shows torque readings up to about 7400rpm.
So it wasn't an RPM limiter, and it wasn't MPH limiter, because I have had it up to 108 a few times in the past, and now was maxed at 96mph. It just wouldn't give me any more.
So what was the limiter?
(Performance affecting "things": PedalBox (I know won't affect top end), RLS cat delete (with baffle--shouldn't matter either, but the 106 days were before the cat delete). Stock tune. Windshield lowered, me crouched down. 93 octane. 98 degrees F.)
I'll have to find another straight and carless opportunity again to verify my memory. No chance in hell I'm snapping a photo with my phone though, lol.