You will still have a good smoke ring and smoke flavor. The briskets I do get a pretty heavy smoke the first 2-3 hours, then I just stay with heat......
The couple of hot & fast briskets I've done didn't have near the smoke flavor or smoke ring as a low and slow or one that's been smoked first. They still tasted good, but I thought were a bit disappointing in the smoke flavor.
If you think about it, at those temps the outside of the meat reaches 140° too soon for much smoke absorption to take place. Also 140° is when myoglobin denatures stopping the formation of a smoke ring. That's why I'm not a fan of hot & fast from start to finish.
You could hit it with a really heavy smoke before the outside reaches 140° (but that kind of smoke can taste nasty) or you could try a stronger smoke wood like Mesquite (not a fan), or black walnut (which is great for beef - like a strong hickory). I could see a smoke tube helping.
That's my 2¢... and heck, it may not even be worth that much!
