Just changed spark plugs on lethargic 95 impreza turbo. Car now goes like stink but I'm getting misfires and splutters I never got before. Worst at 4 to 5 K revs and occaisionaly at take off from rest. I gapped the plugs but maybe I've got a dodgy lead.
Seems odd that the car feels much faster but now spluttering - please help.

 

Possibly 'finished off' a dodgy coil pack when removing them to fit the plugs?