Quote - ...but when I take things to the setup room and apply the DEV Rig, the legs and feet warp or bend.  I'm not sure what I still need to research to figure that out, but I'm sure there's a logical explanation.  If you could point me in the right direction that would be great! ...

This is where a screen shot is probably necessary to diagnose the problem. The figure's mesh shouldn't be warping or bending in the Setup Room... That's probably not what you meant, but see the problem? Interpretation is much better with pics. :D

It's likely that the figure's groups are outside of the constraints of the joints. The mesh is trying to conform, but because the groups aren't lined up properly with the joints, or vice-versa, it will not do that. You need to edit the joints or the groups in order to fix the problem.

The easiest thing to do, first, is to click on the figure and then load up the Joint Editor tool, found under "Windows" in your menu list. Choose the "Hip" of the figure and then "Zero" all the rotations of the joints by clicking the "Zero Rotations" button on the Joint Editor panel. This will move all the rotations of the skeleton to their "Zero" positions. For instance, the Left Shoulder joint will move to "0" x,y and z rotations. Keep in mind that this does nothing at all whatsoever to the geometry of the figure - The Joint Editor only works with the rigging or "skeleton" of the figure, not the geometry.

Next, how does your model look? If it's out of whack, it's because the groups do not line up appropriately for the rigging being used. Either they are outside the bounds of the deformers or they are mislabeled and Poser's rigging does not recognize one or more as valid groups, so it is not applying the rigging approrpiately. You need to be sure all groups have the exact same name as the joint which is responsible for moving them.

Click on a problem group. Look at each setting for x,y,z rotation. (May be bend, forward, backward, twist, whatever...) You can examine each rotation type available for that group by using the drop-down menu on the Joint Editor when that group is selected. Depending upon what type of joint set up you have, and for M4 I believe it just uses standard "Spherical" deformers, you will see different sorts of defomers appear on the model. You may see two spheres, one red and one green, and may see four lines coming from the center of the "joint" with two red and two green or, perhaps, a single line with a red bar and green bar at either end. These are the "Deformers" and each region that they cover is a deformation zone. In order for the group to deform properly, those deformers need to cover that zone and deform the mesh in a sensible way.

Armed with that knowledge, watch this series of excellent vids by PhilC:

https://www.youtube.com/watch?v=PfcPu83gZNs

Watch those three videos, now that you have seen the Joint Editor tool and what it can display. Use the knowledge there to repair your rigging or, if necessary, to regroup your object so that the groups better conform to the existing rigging.

Note: Altering the deformers radically may result in your geometry bending and moving naturally, but not deforming correctly when conformed! :D So, conform the clothing item to M4 and then move M4's joints, one at a time, along each rotation axis, and then switch to your conformed clothing figure and troubleshoot each joint as problems appear.

Once you do this a few times, you'll get proficient enough to do such things in your sleep. :D

Note #2: It is extremely important to have good grouping for conforming figures if you want the conformed figure to deform properly or even pleasantly. If your groups are labled correctly (Check in the Setup Room) and the joint will still not deform the way you want it to, you may need to regroup the figure. In my experience, Poser2012Pro's auto-group feature in the Setup room does a passable job, but not a good one. You'll need to regroup for fine-tuning in a 3D app or your can use Poser's Cloth Room to alter the groups, face by face. (I prefer grouping outside of Poser, using Auto Group Editor, found here http://www.renderosity.com/mod/bcs/autogroup-editor---the-advanced-group-editor-for-poser-clothes-modelers/21081/ . You don't have to even use Poser native formats like CR2s as a reference! ANY grouped wavefront object file can be used, so it's nice for any apps that make use of wavefront objects and grouping. I highly recommend it as well as "Quick Conform." Both are staple utilities in my Poser related lineup.