The fuel and CO2 returns for this LM are, as expected, pretty similar to those of the brand's RX 350h luxury SUV, whose GA-K platform and 2.5-litre Hybrid drivetrain it shares. That means a combined cycle reading of 39.2mpg and a CO2 return of 152-163g/km. Which is pretty good for a huge luxury People Mover of this size and weight.
Whichever kind of LM you decide upon, at higher speeds, you'll need to bear in mind that the quoted fuel figures are even more heavily dependent than normal on the driver assuming a significant degree of restraint. Certainly, for noteworthy levels of frugality in day-to-day use with this Lexus, you'll need to keep the powertrain operating setting in 'EV' mode as often as possible.
On to after-sales cover. It's worth pointing out that Lexus gives you a much better warranty than the limited three year one you'll get with most premium rivals. From the showroom, the car comes with a three year warranty, but providing you continue to regularly maintain it at a one of the brand's franchised dealerships, 12 months of extra warranty cover will be included with every scheduled service, up to 100,000 miles or ten years, whichever comes first. Fixed price servicing plans are available if you want to spread the cost of maintenance, allowing you to spread the cost over two years or more. However you go about paying for maintenance, on an LM it shouldn't cost you too much. The Hybrid set-up has a good record for minimising tyre wear and its battery will last the life of the car. Plus the regenerative braking set-up helps extend the life of the brake pads: over 60,000 miles of driving, the front pads should only need replacing once, while the rear pads and all discs will probably last the full distance.