So, to perhaps sum up:
To integrate canon C3 units, just do it, and prepare a colection of arguments for why BV is bunk (there's a vocal group who feel that way, so shouldn't be hard). To integrate custom units, you may want TechManual or comperable knolage of mech customization, but it's not too hard to do C3 swaps. Some mechs, ones with rear MLs for example, just cry out for C3 swaps, while others with more elegant designs (Awesome 8Q, perhaps?) offer an almost philosophical challange.
C3i was mentioned. It's heavier, 2.5 tons per mech (ten tons for a lance, vs eight tons for a master and three slaves in a regular C3 lance, but no mech has to have the five ton master), but simpler, since there's no one master unit. It can also go to six mechs on one network, but can never grow to company level. The greatest downside is that canon C3i units are mostly Word of Blake mechs, and many of them are.... querky? But, it was also used by ComStar so if you care about canon rationalizations it's not impossible, and if you don't then it's an alternitive worth talking about.
ECM is a huge bugaboo for C3(i) systems, since a little fast mech getting five hexes from your Tai-Sho can mess up your whole world and negate 60% of the BV you hopefully didn't pay for. So if you're up to date on ECM and ECCM rules, that can be a fun little sub battle. If not, see if you're opponent is. It could very well come up.
Lastly, as to company level networks, they're really redeculous, and really fun. But, as mentioned, they're vulnerable to ECM, and they're so clostly under BV as to be more or less untenable. But, with some other system, as agreeded on by you and your opponent, it is worth a try at least once.