[Plums]

Cats don't have any electrical connections, they get up to thier operating temperature using the heat of the exhaust gas.

From a cold start, the closer they are to the exhaust valve, the quicker they heat up, (this is actually called "cat light-up").
The time it takes for the cats to light-up is crucial in emissions testing. This "cat light-up time" is a hard to get right, as different cats light-up at different rates, cat positioning etc. etc.
In fact, the reason the VYII LS1's had the cats right up close to the manifolds, was to improve thier light-up time to help them pass tighter emmissions controls.