The VG Resource

Textures - Check
Sounds - Check
Models - Do u kno da extension.

Short, Simple, Typed..

Im trying to find these model files but any documentation I look for usually are moot for me. (aka not enough info). Thanks!

I think model files are in .prs. You'll need Prsdec, which'll give you .bin files from those. Pretty sure the .bin files are the model files.

I'll give it a shot. I wish they were as simple as VALVE title files, everything in one area!

Only Sonic Adventure 2's model files are stored in PRS files. The models in Sonic Adventure DX are actually stored as C-Structs in the game's executable and DLL files. I recommend you use the SAMDL program, part of Sonic Retro's SA Tools kit, to extract them. Here's a list of the model locations and addresses. Keep in mind that the list is incomplete, though.
https://info.sonicretro.org/SCHG:Sonic_A..._Locations