The Rogue pre might sound different than the Joule but not necessarily better. I think this would be a lateral move. You would have to hear both side by side to really tell. I feel that manufacturer synergy is highly over rated
Don't know about the synergy in that particular system, but I've heard the Rogue Athena and Hera sound awesome into M180 and Apollos, respectively. In the long run, I slightly preferred the Hera II over a VAC Ren III into my Apollos, and that's saying a lot as the VAC itself is pretty special! Either of them made more modest preamps sound sad by comparison.
However, I preferred the VAC's built-in phono stage over the Rogue's Ares in the same system, so it's not always the case that same-company synergy rules.
If you can swing it go for the Hera, but if not then the Athena sounds very similar for a more modest price.