I just converted a bunch of V3 clothes to fit V4 with Wardrobe Wizard last night and it works great!

It's easy to keep the built in clothing morphs as well if you follow Phil's helpful guide.

There's a bunch of Aiko3 clothing I've converted as well. Almost all clothing converts pretty well with WW.

I even converted one of Phil's old P4 Victorian dork outfits to fit Mike3 and it worked like a charm.

I'd highly recommend Wardrobe Wizard