I would like to hopefully clarify "What up?" comments (correct me if I'm wrong What up?)
I think what he meant to say was, make sure you are using any connectors that have low resistance and with a high amperage rating. Some of the connectors that comes to my mind are:
1) Deans Ultra Plug - These are probably the most popular in the high-end (implying high amperage batteries, high power electric motors) electric scene. They are a bit pricey, but hey, they are great connectors
2) Duratrax Powerpoles - These are the ones I use. I don't know how long many of you have been around the RC scene, but these connectors were the KING of connectors a long time ago. Dean's connector at the time came close, but these connectors are more then capable and comparable to Deans ultra...
3) Castle Creations Bullet Connectors - Just visually inspecting these connectors tells you that they are of high quality and can carry TONS of current (low resistance). Its contact points are of very tight fit, telling you that it is making good contact. Plus it's gold coated (copper is a better conductor then gold but gold doesn't work as "hard" as copper). They are the standard connectors that comes with their brushless systems, so you know they chose these types of connectors for a reason.
4) Direct Solder - Ok, these are connectors, but you cannot beat this. Assuming you have a good solder joint, you cannot beat this connection. The weakest link in a power system is its connectors. The wires themselves can carry a tremendous amount of current, but the connection point is often the weakest link... Directly soldering to a point makes the weakest link the wire (which is easy to fix, just step up the size
Any of these four options is good for brushless and lipo combo. Remember that if you are considering this combo, power handling and power management becomes an issue. They're no longer an issue if you pick the right wires and connectors...
I forgot to mention, avoid Tamiya connectors for ANY applications. They're not even good enough for a NiMH + Brushed mod motor applications.