I wish you luck with the catback. If you go out and read the corral or any other board with lots of people that trail and error stuff you will see those numbers were grossly inflated by the Magazine. Most are turning the numbers I mentioned above. Longtubes or JBA shorties will net you much more power for the money.

As for timing I'm running 4.5 over stock. My last dipswitch setting is 8 over stock but thats for 100 octane at the track. All the Cobras get richer as you add mods, the MAF voltage increased with the additional air flow and it really dumps the fuel. A Mafterburner would be a wise investment for any modular car that is doing mods. One of these days I'll break down and buy one myself.

The IAT will add a little timing but it also seems to lean things out as well, thats why I mentioned it. Might or might not work out well in your situation, just something you would have to try and see.

Just wait till you do that gear swap and loose 5-10rwhp If I was still running 3.27's I'd probably be clocking 335rwhp now. Oh well the tradeoff is worth it beyond a doubt.