Yes, Silk, only downside other than cost of catalyst is that they then become unable to be level boosted. So if you plan on only playing high level content you might want to go that direction instead. Alternatively suppose you're an altoholic like me and you have a toon you're only going to use for penny yin tf, e.g. in that case you'd be better off getting level 27 ios and boosting them. They'd still behave as 27 for set bonus purposes but have the stats boosted.
And no desarix, they should be in i24, but the market change that allows recipes and enhancements to change to the level they are bid at is i25 I believe.