Yeah they can go alot lower than Tein Superstreet. They give up to 120 mm of a drop from what I can remember. I had them in my old EK9 for 2 years without any problems.
Also have BC's in the Evo and I find them great. If I had to pick I would go with the BC Racing BR Type Coilovers, slightly more expensive but worth it IMO.
have d2's aswell never any problems with them dont think there is any other coilys on the market that will go lower than d2's and ya dont need new forks as the coilys come with rear forks attached
i Had Daiyama's on me delsol then on to me eg6 had them for just over 3 years, pretty much the same as D2's, Meister R's Zeta's are a good buy for the civic's at the moment, Jerrick's a cool guy, drop him a PM on Civiclife for some more info Mark,
im running Cusco's because they came on the car, very stiff mind, not ideal travel for me 7month old boy lol
my brother brought tein superstreet, had them a 2weeks then sold them for some d2's not only are they lower but they also seemed stiffer. i also had teins on my supra and didnt rate them on that either. dont think you will have any bother with d2's at all.