My dealer has two '05 Saleens - one supercharged and the other not. On the non-supercharged, he tells me that to get the additional 25 HP, all Saleen did was add a pully to the engine. The pully goes front of block, just below the air intake. Thought I would post this, but I'm sure many of you already know this.

 

The Saleen underdrive pulley system for the '05 Mustang replaces the crank pulley with a smaller one and the alternator and water pump pullies with larger ones.
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http://www.saleen.com
You can add them them to your '05 Mustang for a mere $599.99!

 

I assume that 25 hp is a rating at the crank. Figures don't lie, but I know people trying to sell something do a lot of "figuring".

 

The aftermarket kit doesn't advertise gains so I believe that when htwag's dealer refers to 25 more HP on the NA Saleen, it's referring to 325 versus 300 and those would be crank numbers.

 

I thought that the alternator pulley could not be replaced and that was why all the aftermarket companies making underdrive pulleys for the 05s went with just the water pump pulley and harmonic balancer.

 

That's what I thought too and then I saw the Saleen kit. The parts listing does say "Note: A special tool is required for the alternator pulley replacement" which is the reason I had heard that the other aftermarket companies opted for a 2 pulley kit. I think I would have liked the three pullies replaced (but not at $599.99!) For $599.99 the kit should include the special tool but I don't think it does...