Knock knock, your new engine is calling. I bet you have very little oil pressure, as it's all blowing out past your rod bearings. Thicker oil and/or a high volume STi oil pump might buy some time.
If the guide around the crank pulley is too tight, it will rub the text off the back of the belt. Was this clearance set correctly?
Mitsuboshi makes belts for most Japanese OEMs. They do not sell them through the major parts stores, so many people don't realize they exist, but if you start watching, you'll see their name, or logo, on most belts (just did one on my Honda Odyssey yesterday, the original belt said Honda on it, but had the Mitsuboshi logo).
Gates used to use quality Japanese bearings, but started phasing lower quality ones in probably 10 years ago, becoming increasingly more common. You don't have to search very hard to find wrecked engines due to Gates kits. With a little homework, it's not hard to find quality Japanese components from reputable sellers (NOT Amazon or eBay, lots of counterfeits) for a reasonable price.