Re: downpipe removal
Heres how i always did the stocker:
disconnect all bolts, including that stupid tabs on the firewall/wheelwell. Use a mallet to tap the downpipe further into the cat (hit it from on the first bend coming from the cat-there is a decent flat spot there), until the bolt holes on the downpipe flange get off of the turbo. Twist the downpipe towards the fender until it is out of the way of the turbo....and then use the mallet again to tap the downpipe out of the cat.