There is no performance enhancement to the boss H-pipe as the diameter is the same only with side cutouts. We have one lying around that we're not using. We just picked up kooks too by the way, they're offering a shorty style header that will not void your warranty and allow you to either run their "green" high flow cats or stock cats.
Long tube headers in general will require a tune due to the difference in sensor placement, the sensor is pushed around from the engine a good 6 inches. High flow cats require a tune as they will signal a DTC, I've installed a few sets of headers with high flow cats and each kit sparked the DTC.

As far as the mods you chose, I like the shifter. 470 is a bit expensive, there are may places where you can get them for a bit cheaper Also, the FRPP shifter is a rebranded barton industries shifter which is less expensive. However, what you get with the FRPP shifter (****, lock nut, bracket and shifter makes it out to be a pretty decent deal. Give me a shout on the FRPP, Roush parts. Being originally from Livonia MI I have built a pretty good relationship with Roush and FRPP.

The Boss mid-pipe is decent, the sound is completely different. It does a pretty decent job getting rid of that typical "modular sound" we tend to get with the 3V and 4V motors.

Shoot me a PM, you'd be surprised how much money I can save you on a set of Kooks shorty headers (these are being pre-ordered) and heck, I'll be selling my boss H-pipe with side pipes when I put on the full Kooks system.

Jason

 

Did the DTC say it was running lean?

 

More like its running too rich. The car is still throwing all that fuel down there but still can go thru high flow cats triggering the rear 02 sensors.

 

I'm a performance kind of guy, so I vote anything that will boost/enhance the performance on your 'stang.
Good luck.

 

Step1. Go to Obama and apply for stimulus.
Step2. buy all three mods.
Step3. look for more mods.
Step4. Go back to Obama and tell him your still in trouble and need more stimulus for more mods.
Step5. repeat steps 2 thru 5.

 

Them stamps, just glad 1/4 of my check goes to good use, would hate to see them have to get a job.

 

Seriously...I think people that apply for government assistance should be mandated to take birth control.

 

Drug tests should be mandated.

 

Why not, we already provide the Obama phone and government transportation to make and get to the drug deal.