Upper and lower control arms

I went in to the dealer today for a terrible squeaking sound coming from the front suspension of my 06 Speed6. That turned out to be the front sway bar bushings.

I also asked them to try to find a chattering sound the car makes when accelerating. I thought it was engine knock, almost like a low-octane noise. The chattering was caused by my front upper and lower control arms being shot, according to the dealer. $1400 to replace- ouch!

I'm holding off on the control arms for now, but I've got a couple questions... one, does this sound right to you guys? 47K miles on the car and no suspension/wheel/tire mods. Two, is there an aftermarket alternative? I haven't found one yet. Thanks!

Clarification

So I got the car back from the dealer this morning. They replaced the front sway bar bushings and the major squeaking is gone.

They said there are 2 lower control arms on each side of the front suspension. The bushings on these arms are worn and that's causing the chattering sound. According to them there is no way to replace just the bushings on these control arms, so parts are over $1K and labor is another $400.

I may get a second opinion, even though I trust these guys and think they're honest. If it really is a $1400 repair on a car with < 50K miles the chances of me buying another Mazda product are close to zero.

Anyone else want to chime in?

Clarification #2
The same noise started up again almost immediately, so I'm bringing it back on Monday. Anybody have any thoughts?

Advance autoparts carries the lower control arm with ball joint for $127 online and just the bushing for $12

Thanks Mosley. I knew the whole thing sounded a little fishy.

Sorry for the necropost, but you can get all 6 arms, lower and upper, on eBay for under $325 shipped new. The arms are shared with several different cars.