The standard one is more than fine for almost every application!

Moving to stainless looks very nice but also induces the risk of cracking!

On a turbocharged car equal length headers or primeries as some like to call them are not the bee all and end all! In my opinion. Although at 530bhp (on a zetec) I paid the price through heat transfer on a VERY short number 4, transfering heat into the head and cooking the headgasket.

Equal length are the way to go if you can but I am convinced that its not that important up to say 400bhp. That is not including manifolds that are just shit anyway firing into the collector at stupid restrictive angles.

With the very best of respect it sounds like you are looking to spend for the sake of it (guilty of this myself at times). You would be far better looking else where for the best band for your buck!