I have pro 2000's in my car that I bought through a member on here. I'm 180cm/80kg and they fit me fine but at 55kg I think you might need something a little narrower.
Best option is just to have a sit in everything you can.
Standard box street driven.
If you're happy with the car on 98 then stick with it but there are generally always benefits with E85, whether it be more midrange, more power or just overall safety.