More Beautification is simply amazing but it does cost CPU time.....
Take a look at this thread for some guidance on the impact of some mods....
https://steamcommunity.com/sharedfiles/filedetails/?id=1296453455
Big Performance Hit Mods
Do not get these mods if you are already using lots of mods, they will probably lower your FPS by big amounts
1.Added Road Options a.k.a Crosswalks Remover / Road Colors Changer ++
2.81 tiles
3.Extended InfoPanel
4.Advanced Toolbar
5.Extended Game Options
6.More Beautification
7.Find It!
8.Less Steam
9.Telemetry Control
10.Added Ambient Sounds Tuner 2.0
11.Climate Control 1.2.7.0
12.Clouds & Fog Toggler
13.RealCity V1.0.13.18
14.Metro Overhaul Mod and it's required mods/assets
I note some mods and the type of testing is not all inclusive.
But I knew that I had a PC spec which could accommodate Cities of around 500k before I noticed the day and night cycle taking too long.
It was that day and night cycle, timed at 1x or 3x speed, that became my biggest issue. Still at Cities around 750k it was playable but not what I liked in terms of responsiveness.
There is a poster over in the Steam forums, Mark, and I downloaded some of his Vanilla Cities and wow were they so responsive in how they played, around 650k in pop. I was amazed at the difference in how a Vanilla based city ran over my usual heavy modded type.
But once you have tasted cake who wants vanilla, give me eye candy every time
For realistic parking you are just looking at the TMPE mod and then enable the Parking AI. That will leave your roads heavily congested with parked cars, looks good tho with lots and lots of parking zones created. Not sure if that by having many parked vehicles will make a difference in performance for lower spec PC's but at least it makes the city looked inhabited. That was the problem with the Vanilla cities at 650k, there looked to be no one living there...!