Kim for Smoltz sounds about even - a lot more so than it did a couple weeks ago. Still, there's a chance that Mantei could pick up a share of the D-Backs save (unlikely, the way Kim's been pitching, but possible), so I'd probably lean toward Smoltz.
Perez is solid. His value is certainly at a high, so if you want to deal him and get a very good offer, now is the time. If you don't receive an offer that you really like, hang on to Perez - he won't be quite as good as he has been over the full season, but he'll be pretty good.