Full exhaust System for NA yaris

[CASTREX]

Originally Posted by harveyjai

some of my friends have told me to get the 4-1 for yaris...any reason y?
if u keep u rev above 3K, 4-1 is better or 4-2-1?

The DC header mentioned above is actually a 4-1 design. There is only one 4-2-1 header available for the Yaris and is from Weapon R.

In theory a 4-1 will provide a better gain and higher rpm while a 4-2-1 will provide better gains at the mid range. The problem is that by design the Yaris header is so short that I doubt there is much difference between any of the current model available. So I would tell you to choose the one that fits your budget!

If you want the ultimate set up and still keep it legal for emission testing I will tell you to get a high flow cat Only one or at least remove the secondary cat leave the primary cat. You already have a bolt on muffler so you just need the mid pipe.
If you can get mandrel bent tubing go for 2" pipe if you can't get it, then go for 2.25" pipe.
If you want it civil, snap a round mufller/resonator in the middle in place of the OE resonator and ou are good to go!

And the header will make some difference as long as you work out the rest of the muffler. Not much gain by mating a header with a stock exhaust.