Oh hey! Tsukuba circuit! To be honest, I'm always glad to see real life tracks represented in SRB2K in one way or another. Sadly, I do think this pack needs improvement as of right now.
First of all... yeah, the preview pics are scaled very weirdly. Thunder Park is enormous and Tsukuba is tiny. Whether or not this was intentional, I honestly don't really like it though. It doesn't add anything to the pack other than to really mess up navigation in the track selector. I imagine it'd look beyond strange in the voting screen, too?
But as for the tracks itself, I think I can see what you were going for here, since both of the tracks seem to have been "kart-ified". They look a little more like traditioanl karting tracks than race tracks or fantasy racing game venues and all. I think this is fine, but the layout of Thunder Park is a little too boring and simple even for that. 5 very short laps of 6 90º angle turns. The ramps don't even let you go over the walls, which makes them very awkward and is a missing opportunity. I think the detailing in it looks alright, but this track really needs some more.
Tsukuba was what I downloaded this pack for admittedly, but yeah, I think the "kart-ifying" went a little too far here, if that was your intention. The map is bereft of detail, so much so that it's actually a big disorienting to where you are in relation to the track. I wouldn't even notice I was in the back straight of the track until it was almost time for the final turn. Also, having very little off-road sections is a little strange, considering Tsukuba is at some points a relatively tight track. Since you mentioned Gran Turismo and Forza too, it's very strange seeing this track with absolutely no sand/gravel. Overall it ends up not feeling like Tsukuba too much.
I should also mention that the track layout pictures are also gigantic and do not line up with where the racers are. I think the transparency is broken too? You do mention that, but yeah, it's another problem that helps the maps look disorienting.
I'm not saying this to discourage you! I'm very happy to see the interest in porting over real tracks to the game is here! I just believe that you can potentially do better. Try and makes the maps livelier in general, both in layout and in detail.
