I would think (or is it hope) the shorty SuperSprint headers (or any good headers) would make a performance difference on both the SRT and N/A XF.

They are a bit pricey but with some imaginative "make-it-so" financing ...

$2,785 (SS Shorty Headers)
$ 970 (ASP Pulley Kit) (14% SC Boost)
$ 600 (Custom ECU Tune)
$4,355 Total Performance Upgrade Cost (70-85 HP gain??)

That's only $1,055 more then a Renntech pulley upgrade and $1,460 more then the EVO pulley kit alone. That prices the headers within range.

I not sure you can make long headers for the SRT without major modifications, I just don't see the room, plus you would have to relocate the upper CATS etc.. At that point you may as well replace your entire exhaust system with dual 2-3/4 pipes and dual mufflers. (Then if the smog-check guy only puts the probe in one pipe, sniffing three lugs - I might just pass)...

It appears like where the upper O2 sensors are located is a major bottle neck for the exhaust. The SuperSprinters bolt on beyond this bottle neck at the flange, and (if) the headers also eliminate the exhaust port "shroud" issue, then I would expect some decent gains.

I like the plug and play idea, I can wrench in all the above myself with only the O2 sensor relocate requiring shop time and I can have that done before I start removing OEM parts.

Jeeze - I'm really talking myself into this...