Here is my experience with +4's. I have a 91 Galant VR4, it has a 2 liter turbo engine and most of the people in my list suggests NGK's. I have been happy with the NGK's but wanted to try them.
No need to set the gap.
After I installed the +4's I noticed that low to mid was much smoother and what felt like the engine was much crisper. The problem I felt was that at higer rpm's, it felt like it was misfiring.
So if you guys do more low to mid rpm driving then I would suggest the +4's.