[Pampered-Z]

I had different headers on my car as it evolved and all were coated and all rusted somewhat. I currently have the Jethot Longtubes and even though I was very carefully to not scratch them and cleaned them before the initial startup and heat cycles they still rusted slightly around the welds at the collectors. I use Eastwood Ceramic header paint which does a great job of preventing the rust from spreading. The idea with Jethot coating is that they coat inside and out, that helps keep the heat inside the header and will (should) extend the life of the header. Some companies only coat the outside, so the headers simply rust from the inside out. But honestly, almost any coating is going to rust a bit. There is(was) a company that did header coating, it cost a small fortune but it held up. I'll have to go look for their name.

If your plan is to keep the engine mostly stock and driven often, I would say go with shorties, just because they will support mild mods and you don't have the ground clearance issues and such. Unless your trying to get every HP you can, the go longtubes.

As far as what gains, it really varies on the type of header and what you do behind them. Such as cats and Y-pipe. A good set of shorties, such as MAC will give you a far gain, probably 15-25HP. Where longtubes will give you 20-35HP. But all cars are different.