I thought that if you had a joint, you didnt need a pipe.... or vice versa...

In the old days we used to put the ends of the joints in a pipe. Waste not, want not.

Definitely not a MUST IMO, but doing the header and overpipe at the same time seems like it'll be much less of a PITA than doing just the overpipe by itself.

Full Disclosure: I refer to the whole thing between the header and the cat-back as the "overpipe" since some companies sell it all as one piece as I understand it, with and without the race cat, and that's the direction I'm going with my build. There are other names for this section though, and it can be gotten in segments with several different labels like: over pipe, front pipe, joint pipe, test pipe, straight pipe, etc. I apologize for the confusion but there are too many labels for this section of the exhaust.

Free-flowing cat or non-cat shouldn't make much difference, they both flow plenty on N/A engine...FF cat flows about 95% of what a straight pipe will according to my tuner. (Owner of Forged Performance) +10hp/tq was best-case scenario to make a point for him - vs. header alone +tune, tune will give you that +10hp plus other benefits...he'd be lucky to get that out of over/front pipe without tune.

Thanks for approaching it the way you did, I'm always open to friendly discussion/debate and learning something new, so feel free to share any info you feel contradicts my understanding and I'll openly consider it.

Sorry, I refer to the whole piece between the header and the cat-back exhaust as the Overpipe. I should have been more specific. Some aftermarket single-piece replacements replace both the stock Overpipe and stock Front Pipe as I understand it. I assumed that was what he was planning to get.

The +10tq/hp was best-case scenario to make a point, and I agree it would be optimistic, but not impossible. We did net +10 max hp and +15tq at the dip with just a header install, no tune. Another +10 max hp and +15tq at the dip with tuning. So suggesting that header+overpipe/front pipe without tune would only net +10hp/tq seems pessimistic. I would think removing that last cat with overpipe/front pipe would realistically free up 5-10hp/tq, but if you're leaving the secondary cat in with stock front pipe, and just replacing the stock overpipe section, then yeah I wouldn't think it would make much impact.

Here are our results.
Pink is baseline, no tune.
Green is +Tomei UEL Header, no tune.
Orange is after tuning.

http://i.imgur.com/pvZyXJH.jpg

Tomei does call it a joint pipe. Or as everyone else calls a overpipe. It's not going to add 10hp or even close, but it will free up your exhaust, and you'll get around 3hp or so, so it's not THAT big of a deal.

I believe Nameless makes an OP + FP single piece but not sure if OP had a specific part in mind. That being said I've heard great things about the Nameless piece.

I was more referring to the overpipe in isolation, i.e. dyno w/header vs w/header + overpipe would not have a +10hp/tq difference, not the entire header + overpipe netting < +10 h[/tq. Appreciate the dyno results, always enjoy seeing some quantitative data :w00t:

With only rescaling my MAF for grimmspeed intake + OFH using VGI's java program and steve's help, would really love to get it on the dyno and have the tune buttoned up, including timing, load comp, and POL fueling.

Perhaps IAT correction as well but that's harder to do right now with such little info out. Would have to get Drift Office or equivalent the car to accomplish that since I only grasp the basics of tuning these things.

Port + DI rescaling would be awesome as well.. that tuned area under the curve is sexy man, bet she's a blast to drive!