I have the BMR 1" drop springs on all 4 corners. In normal driving and normal size bumps I and my wife do not perceive any increased harshness. I guess it is possible to hit a large enough bump that would allow the struts and shocks to hit the bump stops with the 1" drop springs before the same bump would with the stock ride height springs. I haven't run into that at least not yet. Also, although the springs are rated at 1" drop, my particular car ( and I suspect most others ) saw a drop of ~ 1 1/8" all around after everything settled. The BMR springs are top notch and the improvement and handling as well as looks are hard to beat.
RJT 2SS/RS, AAM 3.70's, MTI Sway Bars, Shifter & SS brake lines, ZLI calipers & rotors, BMR Trailing & Toe Arms, full rear cradle & diff bushings, Pedders XA's, Camber/Toe eccentrics, Radius arm inserts, ZL1 Brembo Brake pads, GTO clutch reservoir, LS9 cam, Comp Cam valve springs, Melling 10296 oil pump, CR 5 timing chain, LS2 damper, CAI Cold Air Induction, ARH LT headers w/HF cats, GMPP touring axle back, Elite Engineering Catch Can, Forgeline 20x9.5 & 20x11 DS3 wheels w/Vredestein 275/40/20 & 315/35/20 tires, '11 Convertible spoiler, Lloyd "SS" Floor Mats, GM Camaro Trunk Mat