Tesla’s Model S electric sedan first went on sale in 2012 offering a then-eye-popping 265 miles of range per charge. In the interim, the sleek four-door EV has added battery capacity as well as many miles to its EPA-rated driving range figures. Now, Tesla CEO Elon Musk has announced the Model S Long Range Plus variant has picked up an official EPA-rated 402-mile driving range. Musk claims that is a first among production EVs—a key win given the impending all-electric Rivian R1S SUV and R1T pickup truck, which are promised to have 400 miles of maximum range but have yet to receive public EPA certification.

What happens in the EV driving-range wars now that Tesla has apparently beaten all comers to the magic 400-mile mark? Well, the debate moves to value—the 402-mile Tesla Model S Long Range Plus starts at $74,990 before any applicable rebates are applied. Tesla doesn’t mention any price changes for the Model S, even with the new range, other than to remind everyone that the Long Range Plus model’s price recently dropped by $5,000—a move surely in no way connected to the upcoming Rivians.

Besides boasting off-road capability and novel quad-motor drive systems, the Rivians have made waves largely because of their promised 400-mile ranges and claimed prices (apparently for those 400-mile-range models) of around $70,000. That’s impressive given how the R1S and R1T will have 185-kWh battery packs nearly twice as large as the Model S Long Range Plus’s 100-kWh pack. As they say, mo’ battery, mo’ money.

How Tesla managed to achieve 402 miles of range (again, according to the EPA; your real-world mileage may vary) from a much smaller battery is a story of tiny, unsexy enhancements mixed with the Model S’s assuredly more aerodynamic shape. The boxy Rivians, though not exactly bricks, have more frontal area than the low-slung, windswept Tesla. The Rivians also are taller, come with more weight-adding hardware, such as those electric motors at each wheel, and are built to deliver rugged off-road performance (read: they’re probably heavy). Also as they say: Mo’ batteries, mo’ weight. This also sets up a situation with decreasing returns: Add batteries and thus weight, and you need even more batteries to gain incrementally less driving range from your extra batteries.

In a blog post on its website, Tesla explains that the Model S Long Range Plus achieved the boost from its previous 373-mile mark by way of mass reduction throughout the vehicle inspired by learnings from the newer Model 3 sedan and Model Y crossover projects. (For fun, we proved it is possible even for that pre-400-mile model to actually go 400 miles on a single charge.) Some weight was trimmed by switching to a modular seat design shared with other Tesla models, while more came out of the battery pack and drive units. A new “aero” wheel design and tire setup is said to improve range by 2 percent alone, while a switch to an electric oil pump from a mechanical piece for the rear drive unit and gearbox optimizations shared with the Model 3 and Model Y are responsible for a further 2 percent improvement in range.

It took eight years and the introductions of two newer, smaller, lower-cost models get here, but Tesla can claim to be first to achieve a 400-plus-mile production EV. Now, let’s see how Rivian—and others—respond.