This table just lists the combined weights of thruster+steering for available atomic engine combos, so you can find something that fits in your engine bay & available outfit space. Bear in mind this list is from the point of view of wanting to go as fast/manueverable as possible. Korath (and to a lesser degree Human) engines are less heat/energy efficient, but this list assumes you are willing to deal with the power and cooling requirements to get maximum engine output. While efficiency varies, with Human and Hai atomic engines a heavier part is always also more performant than a light one. This is not true of the Korath; the Korath Stellar parts are better than the heavier A86, the Planetary Steering better than A525, the Lunar Steering better than Biroo. Additionally some Korath parts are extremely close in performance to the next heaviest Human/Hai part. Those Human/Hai parts are listed, but marked po - probably obsolete. These are the A520 thruster, Biroo thruster, and Benga steering. Remnant parts have the best heat efficiency, but the worst energy efficiency; fortunately, access to them comes with access to the high-density Remnant batteries. The Remnant Crucible-class parts render human A12 parts obsolete. The Forge-class parts are the most performant at their weight, but don't beat out any heavier part; furthermore Korath Lunar-class parts offer much better performance for very small weight increases, so Forge-class parts are only desirable if there is no outfit space to spare. Smelter-class parts are outperformed by Korath Planetary-class parts so are not listed. Wanderer parts are both energy and heat efficient, but generally offer poor performance/mass compared to lighter Korath parts. The only two listed are the Type 1 Radiant parts which are smaller than any other available part, and the Type 4 Radiant steering; all of these are desirable only if there is no outfit space for the next largest part. (They are, however, phenomenally heat-efficient because they include cooling, and if you abandon the goal of having as fast a ship as possible, you can use them to effect a huge reduction in outfit mass.) The bracketed number after each part is the overall tier (eg, "Benga(3)" means there are 2 engines smaller than the Benga, and all others are larger). 21 Both 1-Radiant(0) 22 1-Radiant(0) thrust, Asteroid(1) steering 23 Asteroid(1) thrust, 1-Radiant(0) steering 24 Both Asteroid(1) 24 1-Radiant(0) thrust, Basrem(2) steering 26 Asteroid(1) thrust, Basrem(2) steering 26 1-Radiant(0) thrust, Crucible(3) steering 27 Basrem(2) thrust, 1-Radiant(0) steering 28 Asteroid(1) thrust, Crucible(3) steering 28 Basrem(2) thrust, Asteroid(1) steering 29 Crucible(3) thrust, 1-Radiant(0) steering 30 Both Basrem(2) 30 Crucible(3) thrust, Asteroid(1) steering 32 Asteroid(1) thrust, Comet(4) steering 32 Basrem(2) thrust, Crucible(3) steering 32 Crucible(3) thrust, Basrem(2) steering 34 Comet(4) thrust, Asteroid(1) steering 34 Both Crucible(3) 36 Comet(4) thrust, Basrem(2) steering 36 Basrem(2) thrust, Comet(4) steering 38 Comet(4) thrust, Crucible(3) steering 38 Crucible(3) thrust, Comet(4) steering 38 Basrem(2) thrust, Benga(po)(5) steering 40 Crucible(3) thrust, Benga(po)(5) steering 40 Benga(5) thrust, Basrem(2) steering 42 Benga(5) thrust, Crucible(3) steering 42 Both Comet(4) 44 Comet(4) thrust, Benga(po)(5) steering 45 Crucible(3) thrust, A25(6) steering 46 Benga(5) thrust, Comet(4) steering 48 A25(6) thrust, Crucible(3) steering 48 Both Benga(po)(5) 49 Comet(4) thrust, A25(6) steering 52 Comet(4) thrust, Forge(7) steering 52 A25(6) thrust, Comet(4) steering 53 Benga(5) thrust, A25(6) steering 54 A25(6) thrust, Benga(po)(5) steering 56 Benga(5) thrust, Forge(7) steering 57 Forge(7) thrust, Comet(4) steering 58 Benga(5) thrust, Lunar(8) steering 59 Both A25(6) 59 Forge(7) thrust, Benga(po)(5) steering 60 Lunar(8) thrust, Benga(po)(5) steering 62 A25(6) thrust, Forge(7) steering 64 A25(6) thrust, Lunar(8) steering 64 Forge(7) thrust, A25(6) steering 65 Lunar(8) thrust, A25(6) steering 67 Both Forge(7) 68 Lunar(8) thrust, Forge(7) steering 69 Forge(7) thrust, Lunar(8) steering 69 Biroo(po)(9) thrust, A25(6) steering 70 Both Lunar(8) 72 Biroo(po)(9) thrust, Forge(7) steering 74 Biroo(po)(9) thrust, Lunar(8) steering 77 Forge(7) thrust, A37(10) steering 78 Lunar(8) thrust, A37(10) steering 81 A37(10) thrust, Forge(7) steering 82 Biroo(po)(9) thrust, A37(10) steering 83 A37(10) thrust, Lunar(8) steering 87 Lunar(8) thrust, 4-Radiant(11) steering 91 Biroo(po)(9) thrust, 4-Radiant(11) steering 91 Both A37(10) 93 Biroo(po)(9) thrust, Bondir(12) steering 100 A37(10) thrust, 4-Radiant(11) steering 101 Bondir(12) thrust, A37(10) steering 102 A37(10) thrust, Bondir(12) steering 105 A37(10) thrust, Planetary(13) steering 107 Planetary(13) thrust, A37(10) steering 110 Bondir(12) thrust, 4-Radiant(11) steering 112 Both Bondir(12) 115 Bondir(12) thrust, Planetary(13) steering 116 Planetary(13) thrust, 4-Radiant(11) steering 118 Planetary(13) thrust, Bondir(12) steering 121 Both Planetary(13) 129 A52(po)(14) thrust, 4-Radiant(11) steering 131 A52(po)(14) thrust, Bondir(12) steering 134 A52(po)(14) thrust, Planetary(13) steering 139 Bondir(12) thrust, Bufaer(15) steering 145 Planetary(13) thrust, Bufaer(15) steering 153 Bufaer(15) thrust, Bondir(12) steering 156 Bufaer(15) thrust, Planetary(13) steering 158 A52(po)(14) thrust, Bufaer(15) steering 158 Planetary(13) thrust, Stellar(16) steering 170 Stellar(16) thrust, Planetary(13) steering 171 A52(po)(14) thrust, Stellar(16) steering 180 Both Bufaer(15) 193 Bufaer(15) thrust, Stellar(16) steering 194 Stellar(16) thrust, Bufaer(15) steering 207 Both Stellar(16)