Book install is 10 hours. Most good shops charge around $100/h, so call it around $1K.
Gas mileage is same as before if I'm not driving like a fool, no noticeable change.
The K&N intake may not work, and actually they recommend against using a cone filter due to 'high noise levels'. The exhaust is no problem.
Haven't broken any more belts =P. Stillen replaced the failed belt, and I notched out my hood some more. I suspect that was the root cause, the snout pulley on the blower nicking the hood when the motor rocks on the mounts under heavy acceleration or deceleration.
Also, I just had fun last week running a tank of 87 octane through it. Yes, I know, they say never do that, but sometimes when I'm offroading in the middle of nowhere the only gas available at some podunk place is 87, so I wanted to make sure it would run okay. And yes it did work just fine, with the computer set to the "B" map (retarded timing and richer fuel for towing/bad gas). No audible pinging or anything, though of course I wasn't driving it super hard trying to break it