At my last job, which was "business casual", after wearing my nice clothes for a little while, I noticed that all the other engineers were wearing jeans every day, even though HR said we weren't allowed to. So I started wearing jeans every day too. No one ever said anything to me.
At my very first job (1998), I tried wearing jeans every day too, but pretty quickly got a lecture from my boss. I quit that place after a while, because it sucked (for many reasons). My last job sucked a lot too, and (not coincidentally, IMO) also had a silly business-casual dress code. My advice? Look for a new job. Any place that worries about how their engineers dress is probably not a very good company to work for.
Until that time, I advise wearing crappy, dingy clothes that meet the requirements, and not spending one red cent more than you have to to make yourself look better. Why bother? As for "commanding respect", who cares? Are you an engineer, or a manager who spends all his time in meetings or with customers? I've never felt impressed by engineers who dressed up too much, the ones I most respected were the ones who were the biggest experts in their fields, and they never dressed up. True engineers are not impressed by such shallow things as fancy clothing.
And ties? You've got to be kidding. I've never been any place that required one of those, and I never would work anyplace that did. Those are strictly for the buffoonish executives.
Grisgnakh,