with plugs, i dunno if you know but, what i do is, Get some sandpaper and paper the contact points inside and out top and inside, Clears away all the crap allows for a better spark.
I cleaned out the old plugs i used to have in my spire and put them into the missus's car. With some luck, i screwed them back in and started her. It turned over straight away and fired. Took it down the road and woah.. What a difference it makes!
All i can say really is get bigger sparkleads and better plugs. Are you much into intake modding i wonder?