ERISS: The car becomes excellent when you are able to put better tires, engine, suspension, etc, and it becomes the best car game.
My end car has not the best tires, nor armor, nor bumper, nor engine,
for I want it to keep having good handling on all grounds, roads and off-road, while having a good acceleration;
If you take the more heavy armor and bumpers, you may not be able to jump the farther.
You can't have a car which is the best in all, you have to compromise to better fit your taste.
Indeed. The game kind of punishes you for straying off the road, losing control, spinout and crashing is common off-road, but then you
have to leave the road, whether by choice or not. As long as you keep your speed below extreme and stay on track, it's actually very generous and has a great 'drive feel' much like Flatout or early NFS games. Of course, it's not a real drive sim so a bit unfair to compare to even better 'proper driving' games. I actually really really love driving in this game, it's not quite up to NFSHP2 or NFSMW levels, but it's super enjoyable once you get it dialled in.
The starting car is almost literally a wreck and has a long upgrade path to tune it in to your preferred driving style, it's
critical to get this right.
Too much armour for underpowered engine? Sluggish and you will have trouble staying near centreline, and get bullied by cars faster than you (everyone), drifting into the sand and losing what little speed you had.
Far too much power too control? Car will take off, flat spin, or become unmanageable as it literally flies off the road. Enemy scouts are notorious for this...
Adding handling may seem great but can cause the car to become super-twitchy at extreme speed, or oversteer into spins.
Each body type has it's own characteristics, feel, drive and combat style. Try them all to see what gels best for your play style. I drive massive tanks with super defence to grind down (heh) the opposition over time using a more tactical approach, and don't like going extreme speed but everyone's different. OP should find a style/archangel that works for them
For new players, if you're getting bullied and can't realistically fight back (e.g. chumbuggy) then just drive to a building or a rock and hop out where they can't ram you; even on top of your own car can work, allowing you a clear shotgun shot or risky vehicle takeover a la GTA.
The wastelanders will stop to duke it out with you making it equal rights (and lefts), plus you get a sweet free ride afterwards. Of course if you have an armoury set up, then you have unlimited firepower - shotgun and sniper and 'poons (if you have them) can make short work of all but the toughest enemies, making encounters a doddle, no driving skills required.
I really love the power scale/balance in this game. You start off pathetic weakling and have to struggle just to eke out a meagre survival and your wreck running, later on you become a God Of War, raining down destruction and watching formerly scary enemies flee for lives rather than fight you. Just before you squash them like the trivial bugs they are.
Edit: Some more detail and clarification.