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Are you looking to get BOTH the kids their own car? Or just one for them to share? (Sharing could be a problem. They would have much more fun if they could each have their own. But that could be pricey, depending on what model you choose.)
The Arrma Typhon is certainly a tough and sturdy vehicle. Fast too, on two 2S or 3S Lipo packs. But I wonder if the Typhon would be too much car for kids just getting into the hobby. And this is a personal thing, but I've always thought that the buggy platform, with the front shock tower and shocks just right out there in front, with no sort of cover, was just asking for damage. With a TRUGGY platform, you at least have the lexan body protecting the shocks and shock tower. So I'd look at the Arrma TALION or KRATON over the Typhon for that reason.
How serious do you think the kids are about the RC hobby? The Kraton and Talion are $380. Plus, you're going to need at least two 2S or 3S Lipo packs, and a Dual-Port Lipo Charger. So you're pushing $500. For kids who've never driven an RC?
You might want to consider something a little more entry level. Or smaller. Traxxas and Losi both have 1/18th scale RCs, priced such that you could get them both a car. They won't run on grass (too small) but fine for dirt and pavement, or even indoors. Revel also has the Dromida brand. They have several vehicle types (although they're all the same platform) and they're priced right about $100 each. Or you could look at the ECX line of entry-level 1/10th scale 2wd cars. They're about $130-$160ea. Oh! I just found an 18th scale ECX Ruckus at RC Planet for $99, and it's 4wd too.
So that's my $.02. FWIW.