Cash vs Credit? What's better

Hi Frugal! I'm cross posting this to Personal Finance as well. I am thinking of buying a vehicle outright. What's the better option in terms of credit/points/value? I'd like to get points of course, but if paying in cash means I'd get a better value, I'd be up for that too. I'm just trying to maximize my benefits for a large purchase.

1. Ask for a temporary (if this even exists) credit increase on one of my cards and put the total on the card and the pay it off at the end of the month?

2. Split the cost of the vehicle onto 2 credit cards (no need to ask for increase) and pay it off at the end of the month?

3. Pay in cash?