I'll throw in my 2 cents on the whole topic here. Same as Tcoat I'm here in Ontario where all the highways are 100KPH and most roads are 60KPH. Driving the FRS on the road, there's plenty of power there and usually I've hit the speed limit in the city by the end of 2nd gear. So usually I don't waste my time speeding, since it doesn't really save that much time (only saved 20-30 mins on a 4 hour drive from Toronto to Ottawa) and just have fun with some good off the line acceleration. Especially on-ramps. Same thing really goes for the highway, I just set the cruise control at 114KPH where cops won't bother me and just have fun getting onto and off of the road.
That said, I feel like after taking this car to local road courses and autocross events, my thirst for speed and hard driving is satisfied sufficiently. Setup properly, I've seen an FRS beating most other cars at Calabogie (Ottawa) just because they carry so much corner speed; with nothing more than ~235HP from E85 and a tune for power. So underpowered at a track? Sure why not, but the feeling that you're slow is subjective on where and how's it's driven.
TLDR: Plenty of power for public roads. Speeding not worth the time saved, just enjoy the acceleration. Go to a track or course and have fun with no limits there. Fun being the operative, who cares about more power till you need it?