I was thinking about having my H22a done before I put it in my car. Anyone know the gains from this and if there is anything else needed to be done along with it? Is there any disadvantages?

 

very little gains if any on an otherwise stock engine. and the typical intake, header, exhaust, isn't enough to justify a p&p and valve job.

 

A previous 2.2 of mine had head porting and the gains were good but, head porting is expensive. I put over 200 to the wheels with head porting and bolt on's only. I recommend you really think out how you want to build your motor for the money. Going NA is great because you will run into minimum problems but turbo is more bang for your buck with more maintence.