I'm new to working on my vehicle and plan on doing most of the PM myself to save some money and keep my truck running better since I really haven't done anything besides oil changes since about 30K miles (now at 75K). I have a 2000 prerunner. I recently changed the spark plugs using denso PK16TR11 to replace the denso K16TR11 plugs. the difference is the new ones are platinum. they look like this picture here:
http://www.densoproducts.com/productImages/3/3289.jpg
I had the hardest time gapping them, and then I was recently told that plugs with the double "arms" aren't supposed to be gapped. so I'm trying to find out if that is true, and if so should I replace the plugs (again)? the truck runs noticeably smoother and idles lower now.
thanks.

If it runs smoother I wouldn't change them unless you have problems.