Originally posted by gribbleflix:

I mean like super slow 5years to cross our soler system slow

In "Stellaris/common/ship_sizes" there is a file called "00_ship_sizes.txt" which sets the maximum speed rates for various ship sizes. The asteroid that threatens to obliterate pre-FTL worlds has a maximum speed of "0.1" while a corvette is to set the scripted variable of "@speed_very_fast."

So you could either set it manually per ship type, by typing in something like max_speed = 0.1

Or you could handle it on the system level in common/scripted_variables. It's stored in the file "03_scripted_variables_ships" - so you could just set all the global speed variables down by orders of magnitude. So something like "@speed_very_fast = 0.1"

For now, you can always try Real Space + Real Space: System Scale + Real Space: Ships in Scaling. It's not compatible with other mods tweaking with galaxy generation.

Basically, sublight speed "appear" to be reduced to 1/6 for Tier 1 subdrive. The more you upgrade your thrusters, the more you get closer to vanilla experience at same technological level, and I think that the last tier allows you to travel even faster than in vanilla. The third mod adapts ships to this system scale by reducing their weapons and engagement range (but arguable choices are also made for combat computers...).

A direct gameplay change is that fleets don't engage from across a star system anymore (it's never farer than an inter-orbit separation, except perhaps for strikecraft), and that you have to set manual routes to survey star systems efficiently, because often times, the routing engine can't solve the optimization problem, and you don't want that a survey ship spends another half a year (or worst) in a system during the race for expansion (with tier 1 - 2 subdrive); also this makes survey and anomaly research speed bonus very valuable (as compared to travel speed).

The only drawback of this system is that some event ships are not accounted for yet, and that spaceborn creatures suffer from a massive slowdown, because they don't upgrade their bio-drives (perhaps a middle ground could be to give them a fastest biodrive from the start, but they would become quite a hazard early one _ and why not?).

Tried that but the rings of my planets flouted

It's up to you: you can mod the sublight speed, or you can use RS mods and mod the rings position (I think that old mod zBeautiful Battles (zBB) corrected rings tilt if you are interested). Now RS also lowers the plane of space objects, I believe, to give a 3D feeling.