I don't know about the 100 octane race gas stuff, but on my AT/Step just on 93 octane, OMG!!!
Stock dyno: 265 WHP / 286 lbs.-ft. TQ
Xede dyno: 322WHP / 378 lb.-ft. TQ, + 57WHP / +92 TQ
This thing pulls like I've only experienced in my bro's majorly modded '91 Dodge Stealth TT w/ over 500HP/TQ. I echo those TX guys who said they feel like they're driving completely new animals now. This is definitely an accurate statement. Let's just say that a stock 335i has amazing power (HP and TQ), but with the Xede, it's a real monster! It's got to be much faster than an M3 and ~ 99% of the cars out there. It just pulls and pulls with well over 420 lb.-ft. TQ (to the crank)!
But, you also get the sense that the BMW engineers definitely made the car to handle this kind of power; now we know what this car is really capable of.
I have no idea about 0-60 or 1/4 mi. numbers, but based on stock numbers of 0-60mph and mid 13 sec. for 1/4 mi., I'd have to guess that it's now down to 4.0-4.5 sec. 0-60mph and ~ mid 12 sec. for 1/4 mi.
btw - Shiv was great; he answered all my questions and made me feel very comfortable with the whole process. There was a minor issue at first (after the Xede was all done and we were ready to dyno), but somehow Shiv fixed it, and it runs perfectly so far.
The one thing, however, is that for those ppl not that mechanically inclined, there are a lot of wires that need to be unhooked and put back and it can be a bit confusing even if you label them. Shiv's DIY Video should help with that (he said they're almost done with the video, and it will be posted on their Web site). For me personally, I'd say that taking apart the necessary pieces would be easy but putting it all back together with the Xede hooked up would require some good instructions or I'd just let a professional do it. However, once you know how to do it, it shouldn't take more than 20-30 min.