First, as pointed out by others, it's Rlaarlo, not Riaario. Second, yes, some of their offerings are available through Amazon, primarily thunder their old 'Amoril' name. Third, although most of their original offerings were "rebranded" (and, yes, most likely WLToys), they typically came with better electronics...however, ever since the release of the AK-917, this vehicle, as well as everything released since, has been designed in-house. Fourth, to the Ops original question, these are not "race" cars (although some people have tried using them in on-road racing, to varying results)...these were designed primarily for speedrunning (carbon fiber chassis) & bashing (aluminum chassis). Fifth, in regards to a comment left by Doom, saying they are "a bit on the fragile side", this couldn't be further from the truth (I suspect Doom has never owned the Ak-917, or anything Rlaarlo has released since then). The quality of Rlaarlo's parts is extremely good. Although there was some initial problems with the process they were using for hardening steel, they have since changed the process. As for the plastics, they are just as good as, if not better than, Traxxas, Arrma, and several others, as they are producing a carbon-infused plastic that has a high-enough amount of carbon to make it strong, but not-so-much as to make it brittle. Just because a company is a "Chinese company" does NOT mean it's a bad company, or that such a company produces low-quality products. I own a couple of Traxxas 4Tec 2.0s, as well as a couple Rlaarlo AK-917s (one of which will soon be converted to the AK-787 chassis for dual-motor)...and, being completely honest, if I were to buy another 1/10 on-road car for bashing/speedrunning, I would MUCH rather add another Rlaarlo AK-series over another 4Tec.
Now that I've extolled many of the 'good' points about Rlaarlo, and their vehicles, I'll add some of the 'bad'. While some of the parts are available through Amazon, most are not. This means you must (at least for now) order spare parts directly from Rlaarlo, many of which will need to be shipped from China. Over the past year, the company has been working hard to have parts warehoused in US locations, and the number of those US-located parts has gradually increased...but, for the parts coming from China, those you will have to patiently wait for. Some shipments will be fast (shipped via air), while others will be slow (literally, a "slow boat from China"). Additionally, their customer service has a long way to go before it's up to the 'standards' we are used to from much larger (US-based) companies, such as Traxxas, Horizon Hobby, Associated, Tekno, etc. Some people have complained about contacting customer service, and not receiving a replay for weeks...and, in rare cases, not receiving a reply at all. Thankfully, there are other (and faster) ways of reaching them (for example, via Facebook Messenger). The CEO has even made it easy to rfeach out directly to him...and, for anyone who's had problems getting replies from customer service, when he says he'll get the problem taken care of, 99.9% of the time, he does just that.
The point of my lengthy post is, no company is 'perfect'. Part of the "problem" with Rlaarlo is NOT Rlaarlo...it's that people purchasing from Rlaarlo are expecting the same level of service that they expect from the "big names". They either forget...or purposely ignore...the fact that Rlaarlo is still a fairly new company, and is a small company that's still "learning the ropes". When Traxxas, Tamiya, Tekno, Associated, or any other the other major RC companies, were just starting out, were they providing the level of customer service they currently provide? I'd be willing to bet that the answer is not only "no", but I'd also be willing to bet that their level of CS was not much different from the level of CS that Rlaarlo is currently providing. People have become so 'entitled', with their "I want it yesterday" thought process, that, if the level of service is anything less than "the best", they complain. Is Rlaarlo's customer service great? No...but, they ARE working at making it better. Do you have to wait longer for orders? Sometimes...but, with them getting more products warehoused in the US, those shipping times have greatly decreased compared to what they were a year ago. Are Rlaarlo products high-quality? Yes. One final (related) point - I am aware of some problems with their recently-released 1/7 crawler (which I do not own)...but, I suspect that, just as with the initial problems that affected the AK-917, I suspect they are working at correcting the crawler's problems.