To second jblaine, having a human who will e-mail you directions upon request is a slow, slow process. I have twice received Perrin parts that did not include instructions in the box. Twice, I had to e-mail Perrin for the instructions. Twice, it took more than a day to get the response. Twice, I had to delay/interrupt my installation to wait for the instructions. I have (or have had) 4 Perrin parts on my car, and they have been universally very good, but I tend to do my installs in a whirlwind of activity on Sundays or at night, and neither of these times are conducive to waiting for someone to e-mail me some instructions. Post them!
As far as complaints on the turbo-inlet pipe, I have one, and I've helped MANY people install them on their own cars. None that I have seen have been possible to install "well" without some modification - trimming a little off the compressor inlet point. You can make them work on a stock turbo, or perhaps a vf34 with no mods, but for a bigger turbo, you need to cut. I don't really consider this a serious problem, but you might want to mention it in the instructions.