i would say do it yourself:

1) you get the satisfaction of learning, doing, and accomplishing....

2) you save mad $$$$$

3) and if/when something goes wrong, you will know exactly where and how its all been installed, so you can trace the prob easily and fix it properly.

4) girls love a guy who will trade competent mechanical knowhow for sex

as for the guide thing, ive found several writeups (was thinking of a H22 EK hatch...) for H22's, and they all seemed pretty complete.

so go do some crazy research, find the best install guides, read em over, and if u think you could do what it says, then ur set.

GL