I still think you shouldn't mess with the riff raff
the rockdriver isn't as clear as the celestion higher level line by far
you don't need necessarily v30's
classic 80's and g12h's sound pretty clear, for example
greenbacks a little smoother
if you want a tighter low end from the guitar, best experience I had was with a 1980 maxon 6 band equalizer (same as the ibanez version)
an old mxr would do
I used it as a mid booster and cutting a bit of the lower bass (in front of the amp, right after the wah)
if you don't go wild on the boosted frequencies, it will retain all the clarity and keep your low end controlled
tried the slightly scooped setting like Adam Jones too, and sounds pretty good too, quite crunchy and open
lots of possible settings with different results and won't grind your midrange like a tube screamer would do
tubes can make quite noticeable difference, even if you have good ones already
some sound more aggressive and dry, others are round but gainy and compressed, others are soft but clear
I like the compression of rft's in the preamp
shuguangs sound great, but are too gainy and sometimes noisy
JJ's are supposedly higher gain, but tend to sound clean and darkish
electro-harmonix and sovtek are quite well balanced but lack character
in the power, the svetlana winged C was the clearest EL34 I tried
the shuguangs sound a bit darker and are quite compressed (in a good way, if that's what you want)
I really don't think you should swap that pickup, at least until you improve all the other variables
my first though was nailbomb too, considering the bands you mentioned, but not for your guitar
anyway, the riff raff is still much clearer on distorted chords, although they have somewhat similar voicings (cutting edge, flat paf-like mids, punchy bass)
the nailbomb is a lot more aggressive and low mid heavy