When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
IKH16, IKH20 and IKH22 all can fit. I recently purchased IKH20 spark plugs, but have yet to install them (my life is no longer mine with school starting back up).
You are not going to see any major improvement with the spark plugs. At the most you may see around 1-3 HP gains. The major importance of these plugs is that it will help avoid detonation. These plugs are cooler than stock and they conduct better. This will help keep temperatures down in the cylinders and it will help provide a better spark. In my opinion spark plugs are more in the lines of a tuning requirement than a performance enhancer.