96 civic not running as good as usual

I have a 96 civic ex and I just installed a MSD modified distributor cap, MSD external ss coil, and new plugs and wires. Ever since I put the stuff on it seems like it's missing in the lower rpms. I'm not a master mechanic, but I am quite proficient with working on cars. Any suggestions would be great. Thanks!

i have a 99 civic i put the 6al-2 box with modified cap and rotor and the ss coil...check your grounds..mine did the same thing..it eventuly just had to take it some were mainly because i didnt have the time to mess with it...