I think that wet dry filters are old school. Over time you end up with detritus and chunks clogging the bio balls or similar material. This causes the wet dry to become a nitrate factory instead of reducing it. Many people have been removing there wet drys and using the set up as a sump or converting it to a refugium.
You would be better off having a good skimmer vs. wet dry.
Pre made sumps can be very nice but expensive. I have a Tru-Vu acrylic sump/refugium combo and I love it but I sorta have to. over $300
You will have to spend some time plumbing any sump you get even if it is AGA that will match you tank and you can plumb a super expensive sump as easy a $15 plastic tub from Wall Mart. The plastic tub from Wall Mart is the cheep way to go but you can also use smaller tanks I had a AGA 15 gal aquarium as sump.
Check out the different set ups on this site in the photo gallery and here is one link to web store that sells sumps.
Aquadirect :: Sumps & Refugium
Good luck