From my understanding the street sit below the mono in the Tein range. Mono use a large single piston and are intended for track use, the rates you posted would support this.
The higher the spring rate the firmer the springs. This means hitting a bump with the street fitted you will feel. Hitting the same bump with the mono, you will really feel.
I ran a set of BuddyClubs Racing spec coilovers at one point (which I'm almost certain are a similar design to the mono) and they were lethal as a road set up. Way too harsh to drive with any confidence. You could have read braille with them lol.
Would be worth trying what you have in case it works perfectly, as I said the rear suspension choice plays a large part in actual vehicle comfort on the EP chassis. Could be perfectly rewarding if you get the mix right.