Join Date: Apr 2002
Location: Terrible Hole, IN
At 5'7" you shouldn't need to have the bike lowered at all really. My wife rode an F4 with a seat height of 31.9", but we did have it lowered to about 30" so she could get on the balls of her feet at 5'1". She was fine on it, so I would imagine that you would be too being 6" taller than her. If you do want to lower the bike it will affect the handling in that it decreases ground clearance and you'll scrape metal parts sooner.
When we lowered hers we had it lowered in the front and in the back so as to affect handling minimally. It cost around $600 for it, but we really didn't shop around much. It was hard enough to find a shop to even do it much less be able to comparison shop at all. If I were you I'd go for the aftermarket seat first, if you really even need that. Like I said, at your height you shouldn't have much if any trouble. Most bikes seem to be set up for someone who is about 5'8" or so....to me anyway (I'm 6'2"). Good luck with whatever you decide!
The God of the Old Testament is arguably the most unpleasant character in all of fiction: jealous and proud of it; a petty, unjust, unforgiving control-freak; a vindictive, bloodthirsty ethnic cleanser; a misogynistic, homophobic, racist, infanticidal, genocidal, filicidal, pestilential, megalomanical, sadomasochistic, capriciously malevolent bully. - Richard Dawkins, The God Delusion