[BiturboS4] catback, goooood

[Rich Shiba]

Huh, so i stand corrected. I'd previously kinda spouted off a couple of times
that i felt catbacks are basically about making your car *sound* fast, but i
doubted they did too much else for performance.

I got a good deal on a used Forge/Miltek single, so i figured what the hell.
Replaced it on my MTM chipped A-box car.  Did dyno pulls before/after and
voila, extra hp!  I was surprised actually - i ended up with ~20-25hp more
peak hp and much more linear power and torque curves.  Torque increase wasn't
as dramatic, something like 8 ft/lbs i think (don't have the #'s in front
of me here). Per the hp graphs, power comes on sooner and increases at a
more constant rate.

Anyway, same dyno, similar weather (low 70's), same gas. I'm sure results
will vary depending on your chip, etc, but i'm happily surprised!

     -rich