Question: Do you guys have any special rules for vehicles, or do you basically go by the RAW?
We do have special rules. Like you guys wouldn't have suspected that.
To begin with, where the original books always use a Dexterity + Control roll for driving a vehicle, we always use a Wits + Control roll instead. There are a lot of reasons for this; one is the ever-looming fact that Dexterity, which gives you both attack capability and DV, is already doing plenty in the system and doesn't need to be even more a stat that nobody can live without, but the other is that we think Wits just plan makes more sense. Driving is not usually a very athletic or motion-filled event. You move, of course, but it's all very small repetitive movements, confined to a small space (at least when talking about the majority of vehicles a Scion will be driving). Even little old ladies can physically move fast enough to drive reasonably, so we don't see any reason more Dexterity will make you better at this. However, what really does matter in driving is reaction time - being able to see obstacles or signals in time, being able to avoid dangers or decide in a split second whether or not you can jump something, and so on and so forth. Driving - at least, driving where your stats matter - always happens at high speed, which means that if you don't have the Wits to make decisions in the blink of an eye, you may crash and kill everyone. It's also nice to have two different stats covering different ways of moving quickly; Dexterity is for those who want to move quickly on their own (via speed knacks or things like Marathon Sprinter), while Wits is for those who want to move quickly by using a vehicle instead.
So we never roll Dexterity + Control for anything anymore, really. Maybe in an occasional situational way, like if a giant was trying to delicately drive a tiny car using only his thumbs or something, but not for normal driving situations. This goes for planes, trains, automobiles, boats, chariots, tanks or anything else that normally falls under the umbrella of Control. Incidentally, we also have players use Wits for Control rolls involving live mounts (horses, donkeys, cavalry bears), but usually also pair it with a Charisma + Animal Ken roll to see whether the animal will put up with any of their shit.
As for the stats on vehicles in the books, we ignore them and you should, too. Like the stats for everything in the original books, they're arbitrary, don't always balance well against the capabilities of Scions or antagonists' stats that are provided with them, often contradict comparable stats given in different books because they were written by different authors, and are a big old ugly mess. Instead, we recommend statting a vehicle based on what you believe it should be able to do and survive, with perhaps a tiny touch of cheatery toward the durable to make it more possible for Scions to use it in epic chase scenes or whatever else they have in mind. A normal automobile should require mortals an extended period of time with weapons to demolish, but should be easier to break for a Scion and still easier for a rampaging monster, so give it soak that can withstand mortal averages but not necessarily divine ones. Average speeds for various kinds of vehicles can be easily found with a quick internet search, and if your vehicle is magical in some way - it's a chariot drawn by magic horses, let's say - you can adjust up from there, again taking into account what you think Scions should be able to do with and to it. Feel free to be creative, and don't think you can only use the stats the book normally does. Is it old and out of power steering fluid? Slap a -2 penalty on that thing! Is it a state-of-the-art prototype that's very fast but still untested? Up its speed but give it a 1 in 10 chance of exploding if the Scions go above a certain RPM! Do whatever makes sense and is neat for the vehicle's scene and purpose in the story.
If trying to do that on the fly makes you uncomfortable - and it would for me, so I'm with you - do up some basic vehicle stats ahead of time, whether based on those in the book or tweaked to what you think is more reasonable. Have basic capabilities written down for a normal car, sailboat and helicopter, so you can reference those quickly if your Scions go bananas and start commiting grand theft auto in the middle of their mission. You can also use them as quick bases for other kinds of vehicles - for example, if they're making their getaway in a school bus, use your car stats but give them a maneuverability penalty to their Wits + Control roll and a soak bonus from all the extra steel and seats.
Other than that, I don't think we do anything particularly special. Vehicles straight up trying to outrun each other is still an opposed Wits + Control roll from each driver, although some vehicles may be different enough in base speed that even a Scion's madcap driving skills can't win the day (for example, a moped is not going to outrun a jet, even if the moped's drive is way better at the roll). And, of course, we have a tree of custom driving-based knacks in Wits, which can help a Scion push his ride to the limits of its mortal maker's dreams and beyond.