4 Lane Digital?

Hi all
This is my first post after joining the forum so bear with me if I'm going over old stuff but Ive searched the forums and cant find the answer.
Ive been an analogue racer for many many years and have a permanent track of classic track with 4 lanes le mans starts and 4 lane pit lane,the question is can I extend the circuit to include a large section of digital?
Can I have a 4 lane start and can I keep everything in the classic part or would pits and lemans starts have to go (I dont mind if pits have to go as I could sell on and have digital pits)and apart from the track sections what else would I need? Would one power base power all 4 lanes? And which power base,the old 6 car or the new one
I hope the community can help me and I hope Im not asking stupid questions that have been asked before,many thanks in anticipation
Boggy