Nope, never regretted putting mods in the car. All my mods were carefully researched and they work great as a whole!
The key is to know what you want before you spend your hard-earned $$$. I knew exactly what I wanted and I bought them after researching thoroughly.
My car is several times better than stock in performance. I know it, 'cuz my autoX times show it.
Stock R is great... but modded R is even better.