Are they necessary?

 

No;but usefull,if you want to keep your intake clean.

 

u looking for a oil catch can? I have a cusco one in my s2000 but i dont really use it at all.. i'll sell it to u....

 

If it is needed, then Honda would put it in.

 

Price?

 

If you autocross or track your car it is a good thing to have.

 

^

 

usually its not to bad, but another S2k had such a bad smokescreen he had to pit out, thought he blew something (happens during accelerating high speed right turns)

here was the quick solution

the catch can wont really catch much oil. the reason oil goes into the intake is because the intake is creating a vacuum