10 years ago I bought 2 Durga kits, one to race leisurely at local tracks and one to keep for parts or hoping kit becomes vintage someday. I had a few Tamiya hop-ups on the racing one, the car drove nicely but I was not super serious with r/c racing at the time; unlike some 20 years ago where I used to race much more in middle and high school with sponsorship. I followed similar approach: asking about the track tires choice, playing with setups (gearing,springs, shock oil, diff lube, etc). DB01 ran strong in sportsman class, I didn't want to spend tons of money on r/c racing.
This Tamiya article lists some good performance parts, worth a read even though you got the RR kit. https://www.tamiyausa.com/articles/competition-db01-by-andrew-kuntze-414?article-id=414#.Wj1GNCOnFhE
If the goal is to limit shock travel amount, there are few options beside using the carbon high mount shock tower. If the goal is to make the car lighter and more rigid, then carbon shock towers will give you that advantage.
If someone ever need DB01 part(s), just shoot me an email or PM.