[86MLR]

After testing a Tomei UEL header against a 17+ decated header, and finding no real difference in performance (the OEM was slightly better up top, which I put down to better scavenging), apart from alot more noise, I replaced the 17+ decated header.

Same performance, less noise.

Those UEL headers are loud, and ridiculously loud on cold start, compared to the 4:2:1 OEM EL header.

The OEM header is actually designed very well, it isn't pretty, and could be improved, but, at what cost for what gain.

If you want a aftermarket header for a NA engine, the only thing that I would try would be a nice 4:2:1, pick you lengths for your application, a ACE 250 looks good for my use, I cannot justify the cost to see the difference between it and the punched out OEM, to get that puppy shipped to my door here in AU would cost a kidney.

Why did I go UEL in the first place you may ask, curiosity, there was so much, "UEL will give more torque", or "UEL makes no real difference" I had to try one for myself, against common sense and physics, mainly boredom and the need to play.

A UEL header design is not what you end up with if you use fluid/thermal dynamic in the design process.

I 100% believe it is marketing and the sound that people go for, "sounds like a STI BRO, only slower".

Same same with the focus on the torque dip bandwagon, it isn't really the issue people make out, but if you can sell a few parts.....who is physics to stand in the way of good marketing.

But, don't listen to me, I'm just another punter on the interwebs voicing my findings and opinionated opinions, do some research, check out some point end track twins, make some informed decisions based off sound engineering principles.

As to the overpipe increasing noise, I noticed zero change in noise going from OEM overpipe to a 2.5" overpipe.

Disclaimer: my sound meter is a phone app so accuracy may be a issue.

UEL header and 2.5" catless resonated frontpipe is loud, even with OEM midpipe and muffler.

OEM full catless (punched out) exhaust supports about 200hpatw with a good tune.

If you want as much power as you can get you will need to lose the cats, yes, even 100-200 cell cats are a noticable restriction.

And like always, opinions may vary.......like what people like with their exhaust noise I suppose........

Wow, that got overly involved