I'm 27, only slightly older then you then, and I was introduced to racinggames with GP1, GP2 (excellent! Still have that on my harddrive somewhere) and soon after indeed GPL.
It depends where your interests lie and at that time already I wanted realistic and tricky handling. Because a good racinggame needs to frighten me, so that I break out a sweat and focus. When I'm about to crash I need to have that I'm going to die feeling just before I remember it's a simulator. GPL does that, LFS does that. Atleast in the LX6.
At that time I also had NFS 1 , but although nice for half an hour (or less) to zoom through traffic in some supercar, does not let you die, just get arrested, not the same, although some people really hate to get arrested.
To me it was in the same category as fe. "Carmageddon", etc. (But Carmageddon was a lot better! Now that I think of it, I know how LFS can be improved! )