ChristThePhone
Fractal Fanatic
For the down-tuning stuff, @Moke has a great Eruption preset including a halfstep downtune that works really well. He uses a trick, where the initial attack is not pitch shifted but only the sustaining note.
http://www.custompresets.com/store/p107/'Van_Halen'_-_'Eruption/You_Really_Got_Me'_'Rev_2'_(AX8).html
I recorded a soundclip using it (I cannot play anything remotely like Eruption). First, the riff from You really got me and then a fast (in my book) single note line, changing the pitch back and forth while playing.
I cannot share the specifics of the pitch block, it is Mokes to share, if he wants to, but I can say that it is inspired by this old thread by @simeon http://forum.fractalaudio.com/threads/how-to-reduce-latency-on-down-shifted-patches.57165/
This 'trick' is part of my preset I made for a C tuning. However, it doesn't eliminate the perceived lag, it just hides it somewhat from the audience.