It's a really good question. My Cupra wasn't new, but new to me. I went from a 200bhp FR+ to a 265bhp Cupra. Previously all my cars were <100bhp. I think for me it falls into two categories. Speed and handling.
Speed, I figured +65bhp = 15% smile... therefore + another 30bhp = 23% smile. So it was all about seeing what the car was capable of. Stage 2 was a bit of a lull for me as I didn't really enjoy it. But driving out of the garage with the 2+ on it, it had all been worth it as I proved on the first dual carriageway. In my opinion, speed is more for the lower bhps. Eg I mapped my 170 to 200. If I had a
Cupra 300, I'd likely do Stage 1 and leave it alone. But I also think 370bhp is enough for my MK2 with its limited electronic diff. I have no real desire to make it go any faster.
If we're talking handling mods. I believe my car in the hands of a better driver could achieve awesome potential. I have excellent reactions. But I lack a lot of driving skill. Eg, I can't tell how fast is too fast for a corner until I feel the wheels have already started to slide. And then I lack the knowledge to know what to do to correct it. Bet I'm filling everyone with confidence of me being on the roads! LOL. So I've therefore spent money on handling mods to compensate for my admitted lack of driving skill. I believe if it wasn't for uprated roll bars and ESP, they'd have been pulling my FR+ and my Cupra out of a ditch.