While an aluminum radiator is good for rapid heat dissipation, take a close look at your mounting points. I would mounting using a firm rubber cushion rather that metal to metal contact at the mounting points. Aluminum is noted for developing stress cracks when rigid mounts are used.
That rad does make use of the factory rubber isolators, so it should be fine aside from the general dodginess of Chinese eBay performance parts.
If there's a leak between the tank and core of the rad, your HG just became a prime suspect. Plastic-tanked rads usually don't fail there (you generally will get cracks in the middle of the tank near the neck) unless you're getting pressure spikes, as you would from each combustion event injecting a little bit of blazing hot gas into the cooling system. And since Kia cheaped out on these engines and used a graphite HG (graphite is okay on an all-iron or all-aluminum engine but bad news on an engine with dissimilar metals) rather than the MLS style that Mazda originally used on nearly all the B and F series engines, they're a really common failure point and the layout of the ports between block and head mean that you rarely see the classic 'chocolate milk', it's almost always the tough-to-detect transfer between the combustion chamber and water jackets wreaking havoc on your cooling system (and catalytic convertor, those things don't like being doused in glycol).
The coolant hydrocarbon testers I mentioned earlier are fairly cheap (I think mine cost me like 30 Canadian pesos) and easy to use, and a head gasket is the kind of issue you want to either confirm or rule out ASAP.