Madvapes sells inexpensive 5v box mods... used to have preassembled...prolly still do. I buy the kits and solder them together.
Now, that said, there's a lot of 5v mods on the market. The options (and burden of research) is, I suppose, yours. However the part that concerns me about your post is ....TASTE. Higher voltages can reduce taste. But they give you more "oomph".. more like a cig hit. Also similar to what you get using LR attomizers/cartos. Of course, if your 3.x volt stuff had crappy performance you may find better taste at 5v. Usually, its not quite as good.
You could always get a 5v passthrough and a 2.0 amp or better wall wart and try it out with 3.0 ohm stuff. That would give you a mains powered backup device too.
The good thing about vv is that you can dial in 5v if that's what you want, or lower voltage if you want to up the taste. I use 5 volt because I don't really want to "fiddle" with e-cigs. 5 volts, 3.0 ohm atties and I'm done. But others like the adjustable factor...for taste in particular.
2 cents.