If you want more involved data, or to send messages, it's mostly sniffing, doing an action, and seeing what changes.
`can-utils` has a nice UI for this, which lets you filter messages that don't change easily.
(Also, I've actually never seen a `.dbc` file before, but it looks like a map of PIDs, usually you [or the community for your car] have to reverse engineer those with the sniffing method, afaik)
The ELM327 can technically stream all the CAN messages on the bus and do that type of sniffing, but it has a very small buffer and gets completely hosed with chatty cars.
I personally use the MCP2515 with a Raspberry PI for more involved car hacking.
The electrical modification mentioned is needed for the most common MCP2515 modules because the PI isn't 5v tolerant, but it's an easy enough fix
I have two of them hooked up to a Raspberry PI (one for each of my car's CAN busses, some cars have more), and that with `can-utils` has gotten me pretty far.
They're just generally slower and usually missing features of the newest ELM327 revisions.
The problem is if you just search for ELM327, most of them will be clones, so I just use the MCP2515 when I need lots of data, and use the ELM327 for basic stuff