Impreza 1.6i 90PS tuning?

Hello, I bought a Impreza 1.6i 90hp MY94 a few weeks ago. Since I had a Golf III 90hp before, and was actually quite satisfied with it (but someone scrapped me), I thought it would do it. But the Subi is slower around worlds than my Golf Especially in the 5th gear. Because I am on the highway a lot, but this is my most used gear. But it doesn’t pull at all, with a consumption of 10 liters! Is that normal? My Golf was a 1.8 and has about 8.5 Can you get anything out of a subi like that? I’m grateful for every tip.