too bad you didnt get the full kooks, i think you would have loved itI personally chose Kooks because they were one if not the first company to offer headers for the V2's and I knew fitment wouldn't be an issue.
Installation was time consuming doing it all in my garage with the car on jack stands. You need to removal all the coil packs, then spark plugs and the dipstick tube. Some people say to remove the Airaid to gain access to the spark plug and header bolts but with the right tools it's not necessary. Listen to Rumdog and mark the steering shaft really well and realign it all exactly the same. This is a very key step.
Here is where I struggled. Removing the old manifolds bolts connected to the heads wasn't that bad but the 2 bolts that connect the exhaust to the manifolds gave me a hard time. The driver side bolts took some serious muscle to break loose but the passenger side were seized. Out of frustration I fired up the compressor and brought out the impact gun. Bad idea, it too couldn't break the bolt loose but sure did snap the head off one of the bolts.
The other part I struggled with was disconnecting the O2 harness that is attached to the back of the engine. I literally had to climb on top of the engine and work off of feel because you can't see back there.
Since you're working new hardware putting the Kooks headers on was much easier than removing the old manifolds. The fitment was as perfect as is their quality. My first setup was kooks headers to kooks catless x-pipe to stock mufflers. It had a nice rumble but wasn't too loud and it didn't drone. When I floored it you could clearly hear the S/C whine. I'm one of the rare few that likes loud so i added Corsa Sports. Now my car is f'ing loud. When I floor it all I hear is the motor roaring and the exhaust rumble. I can't hear the S/C anymore. If E-85 is an option then go catless to the stock mufflers. E smells good and the noise levels are very acceptable.