I haven't figured out Lotus yet since I'm yet to work a deal on one (Lotus green pea here), but I deal with this issue all the time with the VW store I work also.
We get a reserve from the banks just by giving them business. It's not a lot, generally speaking a few hundred dollars. Since we work as loan brokers, we can also add %'s to the interest rate, and keep the money there too. The points we can add depend on the bank, but generally speaking it is 1% on subvented offers, and 2.5% on standard rates.
By paying full in cash, you have limited a dealers other sources of income, so against popular belief, you won't get a better selling price. We are generally looking to make $X on a car, so whether it is a combination of a lower selling price but money made in financing, or just a cash deal, the deal you are going to get is generally speaking the deal you are going to get. A $1,000 deal to me could either be $1,000 over what I paid for the car, or $500 over what I paid plus $500 made in financing.
It used to be in the past you could get a lower price if you paid cash, but it has changed. Now both the consumer and the dealer have to look at the total deal to see if it makes sense, and if it looks good on both sides, then both parties are happy.