the "speed chip" is just a power supply connector out of a computer, with different wiring configurations.
dealer on Old Trolley gave me all 3 when i bought my cart. (speed, regular, hilly)
The speed chips are nice if you have a PDS ezgo, since I have a series, which has a simpler system, I cant use a chip. The ease of modification is easier however. I do not have regenerative braking- that is the biggest difference. It allows me to modify my cart easier.
Here is my cart when i dropped it off- (I'll post new ones when i get her back)
You cant use those 12v batts. Even deep cycle aren't the same. Go with golf cart batteries. its the only way to ensure they will be safe and not catch on fire.
But proper 12v wont save you any money- A 12v trojan is $250 or something like that. To save money you would be using an improper battery so I assumed he was talking about using 3 marine or auto batteries.