Spark Plugs are a very important part to tuning your engine. Many tuners say that in countries where gas quality is less than here in Japan, ignition and spark plugs have even more importance in tuning. The key to high horsepower is good quality gas, good ignition, and ignition timing. The Spark Plug has a two major requirements, one is to provide a good spark and the other is to keep cool. If a spark plug becomes too hot due to high boost or high compression it may cause detonation or knock. Detonation, knock, or also called pre-ignition will destroy your engine and should be avoided like the plague. Spark plugs are rated with a heat range from 6 to 10 (rotary engines are 9 to 11). 6 is for normal cars and 10 is for highly modified cars. While there is no specific formula we can offer in determining what plug heat range you need most mildly tuned engines use one heat range higher than stock 6. The most popular and widely used are the HKS M Series plugs but there are many types out there and many different types of engine tunes so it sort of comes down to personal choice. We recommend HKS M Series over all others.

The intake system of your car while effective as stock is hardly up to the task of supporting higher horsepower and performance upgrades. It is important to remove as much resistance while maintaining the integrity of your filtration system and allowing for smooth air flow. There are a variety of kits available ranging from ones that just swap the stock filter with a more performance based one to those that replace all the stock intake piping and air box. They all allow for more air to be fed to the engine and with them installed your engine will feel more responsive. It is important to remember that more air in the intake will not only increase performance but also lean your mixture out. Therefore it is good to accompany an intake kit with an AFC or other engine management that will allow for setting the mixture of you car to match the increased air intake. RHDJapan recommends Trust Greddy Airinx and HKS Super Reloaded suction kits.