I advised an acquaintance to AVIOD buying her son a cold air intake and high-flow exhaust system for a 2007 Honda Accord as a Christmas gift.
My reasoning was that here in Maryland these things will possibly damage the emissions systems and catalytic converter (which are needed to pass state smog inspection every 2 years).
Did I do a good deed or ruin Xmas for a teenage boy?
I don’t know if they DAMAGE anything…but they won’t help. Well they will make it sound different…but that’s about it. If he want’s it…fine…shouldn’t hurt anything.
I would advise the same thing. The money could be used to buy a nice gift.
with a proper setup, it shouldn’t hurt it. However, taking it to a shop to get it’s inspection done, and depending on how anal the tester is, they could fail them for the parts alone.
I’d guestimate the cost of the parts to be about $500, depending on brand and such. That kind of money could buy them a racing game and a decent steering wheel and pedal setup for the gaming system
At best CAI will do exactly nothing unless he’s driving around a track holding the gas pedal to the floor.
At worst:
It can upset the MAF (mass air flow) sensor and trigger the check engine light, plus the little air filter that comes with those things will let more dirt into the engine.
Some of those air filters need to be oiled and a little too much oil will foul the MAF sensor.
If the intake draws air from too close to the ground it can lead to the engine sucking in water in rainy weather, and that will do serious damage.
Exhaust mods from the “cat-back” will only make more noise and turn a nice car into a “ricer”.
Put the $$ towards insurance and maintenance.
A CAI and a cat-back exhaust system won’t damage the emissions system or catalytic converter. They probably won’t do much to help the performance of the car, but they won’t hurt anything. I’ve been using high-flow oil air filters for years, and haven’t had any issues. When I sold my Bronco with 250k+ on the clock, it had been using a K&N filter for 190k of of those miles, and never had an issue. The key is to clean and re-oil properly, many people put too much oil on the filter and that can lead to ruined MAF sensor.
If the exhaust system is a cat-back, and most of them are, then it’s mounted downstream of the cat converter anyway. So that’s not even an issue.
$500 for nothing but a lot of noise…
Another fan of the Fast and Furious movies apparently … 
It’s a waste of money and will accomplish nothing except for what Caddyman mentions (noise) and providing a talking point to his buddies (the CAI and exhaust mod added over a 100 horsepower! Honest!) while they’re standing around with the hood up.
No always. When I was having my Mustang dyno tuned following the supercharger install, a K&N air filter was good for 5 RWHP over a paper filter. Both pulls were done on the same day within 10 minutes of each other. Granted on a n/a car you won’t see much difference, but on a car with forced induction, there can be noticeable improvements.
“following the supercharger install”
That’s the thing. A CAI and/or cat-back by itself will do virtually nothing.
All the links in the chain need to be strengthened.