hey ive got an 03 screw 5.4 4x4 i have already installed a flowmaster cat back single in duel out and i'm wondering if i install high flow cats will it be louder and is it worth it, also how much have people payed to have them installed?

 

It will be alot louder and I paid $160 for labor to have them installed. Check out the link in my sig for the sound.

 

It will sound much better. The same that it does now, just louder/volumed up and a tad deeper tone. $70 per cat on ebay, $80 installed w/ tax sounds average.

 

will high flow cats pass emissions tests?

 

Magnaflows will, they are legal. Theres the 49 state models, & the tree hugger California emission version.

http://www.performancepeddler.com/de...CT_ID=MAG94006

 

are there any people from ontario on here that have high flow cats and have had the emissions testing done?

 

I'm in California, probably as strict as anywhere else, maybe more strict.

I passed the sniffer with Magnaflow high flows & gutted pre-cats. I also had a blower, complete fuel system upgrade and custom tune. I was somewhat close to the limit for NOX but everything else was well below the limit.

IMHO if your truck has cats and a good tune, you'll be fine.

If you gut the pre-cats I recommend making sure the cats stay nice and hot before going to the sniffer. Don't let things sit and cool or the cats *may* not be hot enough.