Wrong, this is a direct quote from Doug at B amachips after dynoing them. He posted a graph as well, the gains started down low and continued all the way to the top, the myth of losing low end torque is false.
doug said:
First off I have to say thanks to Andy that gave me these plates back in November and I've just now gotten the time to install them. Well, had my guy here install them and I went out when they were finished and tuned it.
Finally, the results I've gotten from them were 6rwhp and nearly 10 rwtq overall but in the mid range gains of 7-9 rwhp and 8-10 rwtq from 3000 rpm's and up. At the time for $85 they were a very worthwhile investment, now I think you can get them for around $150 still ?
I drove it and it is truly hard to say if I could feel any difference at all, I could say that It didn't loose any bottom end power to speak of which was what I was expecting. All in all I would say they are a decent investment in the world of $250+ for 20rwhp 6-10rwhp for $100 is worth the money.
In a way, yes. Your tuner will need to turn off the CMCV motors so that you don't throw a code or something. You might also want them to look at your A/F ratio to make sure nothing changed. You can never be too safe