Let me put on my Manual Elitist Jerk hat here for a minute...
There are plenty of reasons to get a Blackwing with the slushbox. Those reasons include, and are limited to:
1. Your left leg was blown off in 'Nam
2. Your left leg was blown off in Iraq
3. Your left leg was blown off in Afghanistan
4. You don't deserve a car like this
But seriously, I have never understood buying a car that was designed first and foremost around driver engagement, and then intentionally filtering out a large portion of that engagement by choosing the auto. Yes, the auto is faster, but then so is a Tesla or any number of other cars that also don't have a clutch. Let's be honest, while you might track or drag your Blackwing, being 0.1% slower at either of those tasks doesn't matter in the least.
But I think it goes deeper than that. If you are actually putting down hard earned money and time to go through the goat rodeo of getting this car, then you are a car enthusiast. And it is my opinion that car enthusiasts who have the means to do so have an obligation to Save The Manuals. If a car has the option of a stick, you must get it. Even if an automatic might work better for you 51% of the time.
Finally, it is beyond a doubt that a manual-equipped Blackwing will be worth more in the future. But are you really buying your car as an investment? No, you're buying it to enjoy it. So allow yourself to enjoy it fully, and get the manual.
Or do whatever the F you want.
