Finally, I start to consider tuning power on my EVO X. It has stayed on Cobb stage 1 since day one. I autocross a lot, so low end torque is important for me.
Here is my planned list:
1. FMIC
2. UPIC
3. Tomei Test pipe (weight saving)
4. Tomei Cat Back (weight saving)
5. Downpipe ??
6. Aftermarket air intake or stock intake + K&N filter
7. 3ports
let me know if I miss anything else.

My questions are
1. Is aftermarket intake better than stock intake + K&N filter?
2. Is downpipe necessary for reaching ~350 whp? I have read somewhere people mentioning stock downpipe is good enough.
Certainly, I need good low end torque. I just done want to waste money on something that's not necessary. Any input is appreciated. Thanks in advance.

 

Typically you can pick up a bit of power with an aftermarket intake over the stock airbox, but it is not a ton, so I wouldn't say it is necessary if you are trying to save a bit of money. As far as the downpipe is concerned, I definitely recommend replacing it especially if you are planning on autocrossing the car. The stock downpipe can run into heat build up issues due to the more restrictive flow which can lead to detonation. This is especially prevalent when running the car hard for extended periods of time.

-Eric