3S-FE header on 5S-FE engine???, Ye Olde Header Question... Options

[sdragon007]

Howdy.

This isn't your usual "I want a header for my Celica GT" post. Rather, it is a carefully researched and calculated question on the feasibility and affordability of future procurement.

I have read in many of y'all's posts that the 3S-FE header can be fitted with slight modifications to the 5S-FE engine. I would like more details as the the modifications.

What exactly needs to be modified on the header?

Who can do such work?
(I assume an exhaust place, but do they need special tooling?)

How much did it cost?
(No hypotheticals please, just real numbers from people who've done it.)

How much gain did you see?
(Dyno numbers would be nice, but if not available, how does it feel?)

Does the catalytic converter need to be replaced with a aftermarket piece due to the one-piece design of the cat and the stock exhaust header?

Anybody have pictures?

Any and all information is appreciated.

Thanks,
Ed

[sdragon007]

Does one need to acquire and fit an aftermarket cat? I hear the primary cat is incorporated into the exhaust manifold and switching out to a header requires a cat?