[RiX]

I gave another visit to Godspeed last week, incrementally adding a front sway bar, a GT Spec Gen 2 header and slightly shortening the midpipe of the GReddy SP2 exhaust a bit for better fit (fabrication).

(1) Ever since this, I am finding that the exhaust note is quiter !?!? Is this normal? The exhaust sounds a little bit higher in tone and much quieter ever since this upgrade that I can actually lower the strero volume during highway driving. Does anyone with a non-stock header experience the same? Dan @ Godspeed thought my exhaust was louder before probably because it leaked before. I am still rather puzzled by it.

(2) Also, now that the new header is in, the undertray covering the header and engine oil plug does not fit any longer. What do you guys do about that? Any downside in leaving it open like that? Is there an aftermarket cover or something?

(3) The ECU was reset but no additional tuning was done on e-manage this time. Apparently not needed with a stock turbo. Oh, well. I wonder more could be expected by tuning for the header alone?

(4) Lastly, Dan told me that I should be able to increase the boost by 1/2 pound of pressure or so. He was rather busy so we didn't get to chat more about this, but if anyone understands why the header makes this possible ... safely ... I would like to understand the physics behind it as well.

The pull / torque seems to have improved noticeably, allowing better acceleration - esp. in the 6th gear. (FYI, I have a catted Godspeed DP in addition to the header and cat-back.)

The front sway bar really improves the handling and noticeably reduced understeer. (FYI, I have front & rear sway and strut bars + Eibach springs) Even with the winter rims & tires, I am turning faster with more confidence.

If I were to go back and redo it all over again, I'd probably go with the DP, header, EBC, both sway bars and Eibach springs as my first mod. Probably e-manage or a better EM device as well.

Thanks in advance for any insight.

[jagcars26]

I have headers installed with a full turbo back,,the headers didnt increase any sounds when installed,kinda suprised me too.

Rudy

[RiX]

But in my case, it actually became more quiet than before... Hmmm.

[Xman]

I'd take a look at the modifications that were done the midpipe as well. The length of the piping before the muffler can have an effect on the tuning of the sound. Taking as much as 2" out of the mid pipe could be responsible for changing the exhaust note in at least part of the rpm range. Typically putting the muffler closer to the engine results in a quieter exhaust overall as well.

[RiX]

Hmmm, thanks for the feedback. Didn't think that the length would affect the sound that noticeably. BTW, the reduction was probably about a half (1/2) inch. Maybe I will consider a different muffler as well, but others who've heard the car actually like the way it sounds now, so I will let the time tell.

Anyone wish insights into questions (2), (3) and (4)?

Thanks.