exhaust

[supra_91]

hey guys whats up? havent been able to be around for awhile. ive been working on my car a little bit and i have a questions for you

Header:
i put on the pacesetter header and the y-extension pipe is really starting to piss me off. when i'm speeding up from a stop normally and when i turn to the left it sounds like it's bouncing up and down. it doesn't do it all the time though. it's kind of hard to explain. i got under my car and i had to retighted the clamps on the extension pipe but it didn't seem like it helped. also after i put the header on my gas mileage decreased a lot, to 6 miles per gallon to be in fact. i called my local performance shop and they said i needed to get an apexi fuel controller. is this true?

test pipe:
just the other day i made my own test pipe instead of buying one. isn't it going to increase the sound? it did a little bit but not a lot. it did however help out a lot. one problem with this test pipe though, when i put it on it made my "bouncing noise" occur more frequently. also when i come to a stop, my steering wheel, dash, and god knows what else shakes. what is up with this? i'm half tempted to take that darn thing out. another thing about the test pipe is that it took the nice sound of my muffler away.

any help would be appreciated