We always assumed (house ruled) that both the Control Rig and internal commlink come with a sim module that is already modded for hot-sim out of the box.
The RCC doesn't come with a sim-module and I don't think it is supposed to have one anyway. Riggers already have a sim-module in their control rig and non-riggers that use a RCC can not use cold- or hot-sim VR nor 'super AR' (where you taste, smell and feel your AR experience), just regular AR (together with DNI or together with imagine link + ear buds + AR glove)
...is that your Speed Limit is what determines how fast your vehicle moves.
That's wrong. Your Speed ATTRIBUTE decides your maximum velocity.
You are both correct.
The Speed Attribute is what you use to see the maximum velocity on the chart on p. 202 (but the chart on p. 202 is flawed and should not really be used as "law" anyway).
However, during a car chase (when you try to catch up or break away from your opponent) the max velocity of your vehicle is not used in any way shape or form. You use your reaction rating, your vehicle skill, the acceleration attribute of your vehicle and the [Speed] or [Handling] limit of your vehicle (and in some situations you might be limited by the [Data Processing] limit of your RCC/Commlink/Cyberdeck).
You don't (never) use the max velocity (or the speed attribute other than the [Speed] limit) in a car chase.
Game mechanic wise you take the complex vehicle action Catch-up/Break Away.
It is resolved with a Reaction + Vehicle Skill test. The test either use [Handling] or [Speed] as a limit depending on if you are in a Speed Environment (major highway or open field) or Handing Environment (winding residential streets or rocky foothills and canyons). Hits beyond the threshold are used to reduce or increase chase ranges (short, medium, long or extreme) by one rank per hit (limited by the acceleration attribute of the vehicle, which for ground vehicles is a number between 1 and 3).
The max velocity of the vehicle doesn't even come into play during a car chase in a Speed Environment with open terrain (highways or flat Plains) where the threshold is very low. Game mechanic wise you still only use [Speed] as a limit to your test. In many urban environments you will not even use [Speed] as a limit (you will use [Handling]).
The only reason a rigger jumped into a Jackrabbit doesn't always catch up with a Eurocar Westwind 3000 on an empty highway is because of the lower acceleration attribute,
not because of the lower max velocity. A reason why a Rigger would catch up is because of hot-sim VR might give him higher initiative (and thus can take the action more often) or if the other driver suck (and can't consistently get 2+ net hits).
Note that (unless you let the Auto Pilot take control or using Manual control) your test will also be limited by the Data Processing matrix attribute of your RCC, Commlink or Cyberdeck (if it is lower than your [Speed] or [Handling]).
Also note that (unless you are using manual control or are considered directly connected) noise might act as a negative dice pool modifier to your test.
