Mind you, that I'm jus an ol' man on a bicycle,... and rather new to the "e-bike scene". AND,... I'm very understanding of the OP's desire. I would have installed a nitrous boost had I gone to IC engines instead of "battry power"! Instead, I studied (many thanks to the wonderful members here) and shopped carefully to be certain my needs would be met in my initial purchase.
Currently,...
Cheap 29'er 7-speed cruiser from BB store (PLEASE forgive me)
Leaf Bike 1500w 48V rear hubmotor conversion kit on a 700c rim with Big Apple
Lunacycle 52V Panasonic PF 11.5ah "Performance Pack"
The Leaf kit controller allows 40A max (battery allows 50A continuous),... so I've got EVERYTHING I wanted, everything I hoped for, and more.
I often set cruise about 20mph, leaves me with some reserve if I need it. I luv arriving at a stoplight as the brake disengages cruise. Jus an ol' man on a bicycle. But when the green comes,... I AM GONE!!! Leaving the leading cars, they often accelerate a bit more even as they notice the ol' man on a bicycle is STILL moving out ahead!!! I'm in my "sweet spot",... and at about 25 or so they begin to gain quicker and are finally along side me at over 30mph!!! By the time the following cars are up to me, I'm doin near 40!!!! Now this is country highway stuff, where the speed limit is 45 or better. NEVER underestimate an ol' man on a bicycle!!! Motorists are often stunned and shocked in this scenario, and I luv it!!!
In the city,... under 35mph limits, I'm jus part of traffic. And a considerable bit quicker than most anyone else on a bicycle. Well,.... till a squad unit appears. Then I'm jus an ol' man on a bicycle,... peddlin' like all get out!!!!
I knew "upgrading" and modifying would be far more trouble than it's really worth. I'm glad I somewhat anticipated all my desires and needs in my initial purchase. Although I do sometimes wish for a disengagement of the brake switch,.... pavement burnouts with a locked front wheel at the stoplight would fun. And some punk in a quick car would likely capture much more attention and trouble than I,... hehehe.
I really gotta find me one of those "juiced" IC bikes,.... bet I'd beat 'em off the line AND in the stretch!!!!!
Nitrous,... HA! That's "old school" stuff today!!!! Who needs it!?!