Ok, I'm currently uploading a shitload of pictures that I have of various toyota race motors. Because I can't be bothered specifically labelling them, all the pictures of the engine parts (intake ports, dry sump components, cams) are from an engine Toysport had on ebay as a 503e. I believe this is in fact simply a heavily modified 3sgte. This appears to be very similar to the engine pictured in the "2003 JGTC GT300 Class Engine Tuner Champion" picture
The other 4 cylinder with lots of pictures is, IMO, the 503e (ie, the real deal 4 cylinder race motor). This is the motor in the dragster, in the photos where it's on a stand like it's in a museum or something, in the eagle mk3 gt race car (hint, look at valve cover design). Amoung other things, you may note features that make it reasonably unique, including the head with an individual coolant inlet for every cylinder just above the exhaust ports. It also has very little water jacket to speak of around the cylinders (much higher strength than the 3sgte block which is in the toysport pictures)
Finally there's few pics of some old open wheelers with what I believe is a 4T-GT race motor, and a random picture of a v8 (*UZ) from some american roundy-roundy racing league.