Well... first re-read the rules concerning dice pool modifiers near the beginning of the book. That part right there is really the only limitations you have concerning the size of the dice pool modifiers your players will be getting and if it is overlooked, it is way too easy to get a pool of 30+ dice for just about anything.
Second, make sure that everyone understands that combat in SR4 is not supposed to evenly share the spotlight among the players. If four players have 3 IP and the last person only has 1 IP, it will work as: Everyone's First IP, in order of initiative (PCs and baddies), Everyone that has a second IP, in order of initiative (the other 3 PCs and a good number of baddies), Everyone that has a third IP, in order of initiative (the other 3 PCs and a few number of baddies), End of Combat Turn. Repeat.
That person with the one IP will be going something like once per half an hour while everyone else will be once per 10 minuts.
It is tempting to add in all of the other books since they are available on pdf, but unless it is absolutely required, don't do it at the start of game. Yes, it will present more options, but it will also slow things down, looking stuff up, rules checking, reading the errata, reading the forum when the errata is lacking, etc.
When making the characters, set certain options to be the default options to speed things up. Force is always the Magician's Magic unless stated otherwise. Multiple-Round bursts are always Narrow Bursts, unless Wide Bursts are specifically chosen, etc. Also, make sure the players know the dice pool for anything that they are likely to do a lot of. The adding and subtracting of dice is probably on the parts that slows the game down the most, because it happens so often.
Lastly, something that should have been mentioned more clearly in the main book:
Drones and Vehicles have commlinks / nodes just like your player's commlink. The default rating for the Firewall, Response, Signal and System is 3, with things that designated 'security' having a 4 (and no there is no clearly marked security attribute) and those that are 'military' are 5 (and again no clearly marked attribute... *shrug*). Like all commlinks, the System cannot exceed the Response rating and no program rating, including Pilot, any autosofts, or anything else, can exceed the System Rating. These can be upgraded, altered and hacked just like any commlink.