I decided to go with 8 wheels, using the Trumpeter LAV-25 wheels which are thicker than the kit's wheels:
With an M113 top:
Nose is long; I have to trim the top a bit and eventually add the bow plate:
Adding the M113 rear was pretty easy and took very few mods:
I used some M113 (I believe) wheel backs to mate to the Trumpeter hubs. It was easier than trying to drill holes to match. The M113 wheels fit the LAV-25 well with just minimal trimming. I used wires to make the two front wheels movable. The track width is pretty wide now; I'll need to add side panels or shorten the wheel mounts to reduce the track width:
While it looks OK, the new vehicle looks (and is) very large compared to a stock M113. I shortened it in a graphics program to roughly match the length of an M113:
I'm still debating the change. I found an M113 hull that I had already spilt a while ago, so I can just replace the sides and trim the LAV-25 lower hull to match, or just cut new sides to match.. The longer white sides can be used on a lengthened M113 project.
This is a length comparison: