ST205 - Replacing all 4 rotors & front caliper rebuild, DIY - I did it. Options

[Jeebus]

Hey folks,

So when I last took my GT-Four to get my new wheels (to a performance garage), the mechanic told me one of my front calipers was seized, and my rotors were not in the best condition (pads looked new though).

I've gone ahead and bought replacement rotors and received my caliper rebuild set in the mail today, but I'm not quite sure whether this is a task I should do on my own with my limited mechanical experience, especially working on something critical like the brakes.

I've phoned the garage, and they've quoted me 4~5hrs of labour.

I've also looked around the web to see some FAQs and have found these two DIYs:
GT4dc.co.uk
GT4OC.net

Now the question comes to this, should I save myself $350 in cash and attempt this on my own, or get it professionally done?

The part I'm most unsure about (since I've never done it before) is working with the brake-line (bleeding and such).
What will be the most difficult & critical part if I decide to do this task myself in my own garage?

This post has been edited by Jeebus: Feb 13, 2014 - 2:31 PM

[Jeebus]

Looking at those links, what would make a piston unusable? If there is a little surface rust, ive read on some other sites that Iyou may be able to use a high-grit sandpaper to rid of it and re-use it.