do I need only the lower engine mount? or both upper and lower?
and will I notice performance gains w/o high flow cat and cat-back? (I ll buy them later this summer) or should I go with cat-back first?

if you do just the header, you wont see much as for gains. Honestly i would do the whole system at the same time, thats what im gonna do. i would say that you should bo good with just the lower mount, as the upper for the ecotec is quite a hit on the wallet.


Ill make a sig someday

wait you need a lower engine mount to use a header for an eco??

no mounts needed. do the catback 1st


Working on obtainting an M-Class license... ?? Hint: 2 wheels.

for a regular header, it's not required to do the mounts also, but suggested. the reason being is so you don't break welds when the engine shifts on start-up or normal accelration..

however, at least the lower mount is HIGHLY recomended if you use a cermamic coated header. this is so you don't crack the coating by having the engine shift.

You could also use a flex joint and probally not need to worry about the mounts.

As for me personally, I ran 6 months with the pacesetter armor coated header with the lower poli mount and stock upper mount and had no problems. quite a few people here are set up the same way because the upper poli mount is so expensive.

the ONLY reason I have the upper mount is because of the O2 sensor mod I had to do. My car didn't like my high flow cat. So, when I added in the spark plug anti-fowlers, my O2 sensor got spaced so far out that it would rattle on the undercarrage. The upper mount fixed that problem.

DeadBob is right...
For the Pacesetter, you dont need the mounts. Their header is designed so that head gives a little at the down pipe. Now it's highly recommended that you use the mounts or at lease a flex joint. I myself am only using the lower mount, and the stock upper...
I would advise you do the full exhaust at one time. you see better gains.
If interested, I could get you a good price on a pacesetter header. just email me.