Seems like a great mod. maybe an earlier replacement for circuit networks or maybe to create sub networks etc. But how does the performance get affected by this? I mean both ingame performance (UPS/FPS) and the bots performance when compared to ingame belts.

If we are unable to craft anything on roads that means they are basically belts. But how does 22kmh and 1capacity per bot translates to belt speeds? How many bots do i need to move 15 items per second and i assume it will be a huge amount so how about ups?

1 capacity is pretty devious, since it means its 1 stack of item, so you transport for example 200 plates at once. And it can be up to 5 stacks at once, so they could push quite a lot of items at once, even if they are a bit slow at beginning.
Also with optimalization to pathfinding they are doing, the ups seems pretty good with ~3k of drones driving around in grid-based base for both short range and medium range. UPS stable at 60/s, with base of around 2.5k spm on Krastorio2. They get pretty wonky when you up them to ~88kmph (they miss their turns since they go into turning like Tokyo Drift:) Even with pretty much basic upgrades, transport drones gets pretty crazy with throughput, so they are great replacement for trains for short to medium distances (up to ~25 chunks of distance between depots).

So, they are pretty neat and have potential to carry out late game pretty comfortably:)

They get pretty wonky when you up them to ~88kmph
Do you happen to know what level of the speed research that is? Sounds like I should avoid it.

Its 14th level. They do drift a bit, but I don't think that impacts them more than pathfinding, the road they take with bigger speed or not is usually wonky enough:)