I really want the handling to be right on this game, we can't do a simulation but, we can come close. A perfect balance between sim and arcade (GTA 4, NFS pro street).
Yeah, but IMO we should decide which elements will be closest to one of three choices. The first choice would be "Fun". Think Saint's Row 2 or 3 when you think "Fun". It's not balanced, it's not realistic in any sense, it's all about player experience. Unfortunately, most things are unbalanced as a result. The second choice is "Balance". Think about how GTA4 weapons and vehicles work, as well as their possible combinations and intersections. That's balance. Not necessarily fun or realistic, but this way there will be an upside and a downside to everything (i.e. you can tune up your car for racing and beat other racers with ease, but it's expensive, maintenance is expensive, gas is expensive, etc.) The last choice is "Realism". Self-explanatory, but not necessarily balanced or fun.
As an example, let's say cops are more Fun. They give out $25-$75 tickets and you never get a record, maybe they'll try to ram you off the road if you don't stop, but some players will curse at their computers when they get rammed off the road (wrecked) and it's really not realistic at all. If the cops were mostly Balanced, they'd give out $50-150 tickets, however they would touch the player car as little as possible, maybe get in front of and slow down the player car (by pressing their back bumper to the player's front) or PITT the player. If they were mostly Realistic, they'd give out really expensive tickets ($100+) and be nice unless the player gave them a reason to be harsh. This could bankrupt players quite easily, and the added realism would make for added difficulty in evasion, however the player's options would open up a lot more.