With the coming changes to the Borg set, you really need to know this.
The jem and breen engines both Fail because they are Combat Engines, and their perks are only marginally better than Blue Gear of their level. (they are Inferior to some purples) No One in pvp, that has a brain can actually get the benefit of a Combat engine. Everyone's engine power that Matters, has 54/25 engine power at minimum. This is due to warp core efficiency, power generation and engine performance. Combat Impulse stops giving bonuses at 50 or higher. This is why that engine went the way of the dodo over the last couple of years.
At the very least the breen and Jem engines need to be Standard Impulse engines. This is only a minor buff at best true, but it's alot better than what we have now in pvp. Ideally you would make them Hypers instead, since it would actually encourage people to play your lolpve.
It also would make them almost worth considering in the final game.
Neither shield is a Cap3. This is another huge detriment to the set. Neither shield has anything resembling decent shield regen either.
If you make the shields cap3, they'll still be inferior over all to Maco, KHG, and Omega however people will actually use them instead of Blue Cap2s in pvp till they can get their Great Stuff.
These two changes, would make the Breen and Jem set decent stop gaps until someone could get their Maco, borg, KHG, or Omega sets. (yes the reman set sucks, and yes it sucks so bad that I'm not even going to mention it in this thread as it's revision needs to be considerably more Extensive than what this thread can offer. If you think this post is long imagine an entire post this long or longer dedicated to Just the Gimpy Reman Set) Seriously, Blue Gear for engines is just as good, and Purples are better. Both of which frankly are much easier to acquire without playing silly lolpve. The shields are only about as effective at best to Cap2 shields. Which are very easily acquirable.