Interspace-10
First engine able to traval at warp 10 without taking damage. Made available by the lesser racial trait No RamScoop Engines (NRSE).
Ships sporting an engine unable to engage warp 10 without taking damage have a 10% chance of getting destroyed midway during transport each year they travel at warp 10. This limitation is per ship, not per fleet, meaning that each ship would individually have a 10% chance to be destroyed inside a fleet while attempting to warp above the safe limit. A ship hull requiring more than one engine in its design do not increase the likelihood of destruction.
Because of the need of fast warp 10 capable engines in fast and short games, many players are fond of the IFE and NRSE combo. The access to all ramscoop engines short of the fuel mizer is then sacrificied for access to the first avaible warp-10 engine in the game: the interspace-10. Because of the incredible versatility of the fuel mizer, many players do not consider the ban of the other ramscoop engines to be a real liability and thus enjoy the points the NRSE LRT give out as a way to balance the cost of IFE.
Further, players using NRSE often consider selecting propulsion costly at race creation and then plan to never research further than level 12 for the overthruster, the interspace-10 already acquired at propulsion 11. Doing so allow to concentrate on other fields for the rest of the game without having to bother with propulsion again while still being able to rely on a very fuel efficient engine for non combat ships (the fuel mizer and an efficient warp-10 combat engine (the interspace-10).
The overuse use of this engine is however not without its downfall as its cost and weight are very high in comparison to other more traditional engines and can quickly add up. More poweful hulls requiring a higher amount of engines to deploy, 2, 3 or 4 interspace-10 on a single hull can greatly increase the final amount of resources required to build and/or greatly reduce the gatability of the end ship. This extra cost can still often be well worth the price in certain situations, especially on surprise attacks between 81.5 and 100.5ly. The advantages of being able to move faster and easier than your oponents long before they are able to reciprocate is also a non-negligable advantage.