For 4 years I put up with minor annoyances in the standard audio system due to lack of reasonable bass, clarity and presence. The LH replacements fixes all those issues to an acceptable level. Look forward to driving just to hear all the different music again on an improved system. But now the highs like cymbals and high hats in certain rock songs sound slightly distorted and I'm thinking it's the stock tweeters that can't keep up with the LH so looking for replacements. Will probably try 1" off the shelves first.
Was also looking at NVX sub the same time, however now with only the LH upgrade there may enough bass to satisfy most types of music I listen to. The major thing that stands out is that at any volume, even at a '1' setting, the response and quality of sound is very close to that at higher volumes with the LH speakers. In the standard and even UHFS systems I've noticed at low volumes the bass typically disappears, very inconsistent when compared to at higher volumes.
I notice you had UHFS in the past two cars but perhaps not in the most recent one, were you not happy with the system? There was no UHFS (or Studio Sound as it was called back then) to demo when I purchased so I didn't include it as an option. At $950 back then I later wished I included it when I heard the difference. At $2,500 now I would rather opt for LH and NVX which would be the better system, cheaper too if self installed.