Just on a whim I wanted to make up stats for some of the clone-wars era weapons for my players to come across, either in the hands of enemies or on the market, for them to use potentially. But I'm having a little trouble trying to find what would be considered balanced, I guess.

The item in particular is the DC-15S Blaster . I want to make this weapon unique in the way that the SC-14r is different from the standard blaster pistol, but the only quality I can discern to make The 15S different from the Standard Blaster Carbine entry is to give it Breach 1, based on the fact that wookiepedia claims this weapon was "...more than capable of penetrating heavy armor". The alternative is using some degree of pierce.

I'm not sure if this is too powerful however. Does anyone have any ideas what I could do with this weapon?

The E-5 on the other hand I'm giving a hot barrel, forcing the wielder to suffer 2 strain and 2 wound if they have 4 threat on their roll. It punches for 8 at medium range, crit 3, 900 credits, encumberance 2 and rarity 6. This is the weapon fielded by the legions of battle droids during the clone wars, and Wookiepedia talks about how the gun was fragile and was designed for droids but had a powerful blast.

I also want to do something for the DC-15A and make it like a blaster rifle with extreme range. Anyone have any similar thoughts for these older weapons?

Both of those look like regular blaster carbines to me. I wouldn't read too much into the "penetrates heavy armor" fluff. A carbine is more than capable of punching through just about any soak your average opponent has.

Remember, the core weapons are abstract weapons for an abstract game. But if you do want to make them unique, give the DC-15s a point or two of pierce and the E-5 could have inaccurate 1 (1 setback) when not wielded by a droid made to use it.