Given that the Sport throttle map doesn't actually change the performance of the car, it's no surprise that the mode that feels "best" is simply going to be the mode you're most accustomed to.
If you drive around all the time with the "sport" throttle map engaged then the non-sport setting is going to feel sluggish and unresponsive to you. If you drive around all the time with "sport" disengaged then the sport mode is going to feel twitchy and oversensitive to you. The bottom line is that the car isn't any faster at all with the setting on or off.
Personally I don't care for the loss of precision with the sport throttle mapping engaged. I find that switching back and forth is bad for me because sometimes my brain forgets to tell my foot that the throttle mapping has changed and I end up accelerating too much or too little, expecting the other map. Switching back and forth between the two mappings is worse than having just one or the other -- the inconsistency is bad.
I can see the "sport" mapping causing problems at the limit in a sweeping corner where you're balancing grip to carry yourself through the turn. In that sort of situation I much prefer having more control over the throttle than less, and the sport mapping definitely gives you less control over the throttle.
Seriously -- if you don't have SC you'll never ever miss it. It's not like the car is any faster with it and your foot won't care. If you do have it you might find, like I have, that it's worse to have the choice. I'd rather become intimately familiar with one throttle mapping than mentally juggle which is engaged at any given moment.
Since the sport setting comes with the ugly dashboard wart (you either love it or hate it -- but either way I can guarantee you'll never
use it) the option becomes even less appealing to me.
About the only arguable benefit is the supposedly more relaxed third setting for PSM. This is actually what encouraged me to get the SC in the first place. I find, though, that in reality I'm quite content with the normal PSM setting. I was expecting PSM to be as invasive as the DSC was in my M Roadster but I was pleased to find that Porsche's PSM is much more lenient and I'm quite able to steer with my right foot and drift a bit with PSM turned on. It's sportier than I'd ever want to be on public roads. When I autocross I turn it off anyway, so I don't know when I'd ever really use the third "sport" setting for PSM.
The extra twiddly bits that the SC enables in the PCM (door lock options and interior light options) are totally trivial and your dealer can set them up for you even if you don't have the SC installed anyway.
I don't recommend it, irrespective of cost. Heck, I'd pay extra for a "wart delete" option.
