I spent the past weekend installing Stillen headers, Berk cats, and a Bassani exhaust system on my 07. I did everything in my garage, on jackstands, with hand tools, by myself.
The Stillen headers fit like a glove, and the only non exhaust parts I removed were the 2 intake tubes and the steering coupler, which was a cinch to remove. The hardest part of the removal were the heat shields on the factory headers. I never did get the drivers side bottom heat shield off, but the header dropped out with it on. The hardest part of the install was tightnening a couple of the bolts on the new headers, especially the bottom center drivers side. They had to kidding about torqueing those header bolts back on. There were some I couldn't get a ratchet of any size on, much less a torque wrench.
The only hard part about the Berk Cats was the removal of the top bolt on each side, both of which broke off, which eased the process. One of them required a 4 foot piece of pipe over the ratchet to coax out.
The Bassani exhaust has to be pieced together carefully like a puzzle to get it together in one try. I found it easiest to remove the hangers with the rubber insulators from the frame rails, so I could remove them from the old exhaust while laying on the ground out in the open, and install them on the new exhaust, also laying on the ground out in the open. It also made the install much easier.
The down side to the Bassani was that it did not clear the frame brace that runs across the tunnel and goes back to the rear on both sides. I ended up bending the Bassani exhaust up some (with all of the exhaust in place, but not tightened up), and spacing the brace down some to provide clearance. Maybe this brace was added in 07. The exhaust is made for the 03-06, and Bassani told me it would fit my 07, but that is not what I found, unless I removed the frame brace and left it off, which I didn't want to do. I bought the Z for it's handling, and that brace would be a plus for handling.
I ran just the Berk cats for a couple of weeks, and really liked the sound of them with the stock exhaust. I haven't driven it enough to know for sure yet, but I think it is a little louder now than I would have preferred. The mid range does feel stronger, which is a big plus. My experience so far....

 

wow....Long weekend huh

 

fixed

 

you a$$

 

Which bracket are you talking about that wont let you install your bassani?

 

The bracket is shaped like a Vee, with a flat bottom, pretty large, about 2-3 feet per side. It bolts across the floor plan tunnel roughly in the middle of the car, and then goes to the rear, bolting near the rear control arm pick up points on the frame just in front of the rear tires on each side. It was painted black steel. The bracket interfered with the Bassani pipes with the resonators that attached to the X pipe, so I modfied things to get it to fit.

 

Hmm I have an 07 350z with the Bassani Exhaust.. it is a puzzle to install, however my exhaust did clear that V-brace underneath the car. You just need to put something under it while you're putting the pieces together and make sure everything is tighten and everything is on a hanger it should clear that brace by 1/2" atleast.