Re: Technical Pups
In my experience, clarity under heavy distortion comes from having a good amp with a tight pre-amp that let's you control the sound without the bass becoming overpowering and the mids fizzing out. Personally, I get really good results with the X2N for playing fairly technical stuff - it's also the pickup that Chuck Shuldiner used. It does muddy up for complex chord voicings, but IMO it's the best and most aggressive pick-up out there. The Dimebucker is a lot more blunt IMO and I wouldn't recommend it - probably the least successful SD pickup in terms of sound, i think....
Active pick-ups, like Emg 81 and SD Blackout certainly do the job, but somewhat mechanically, IMO. I found that I can't really get the same monstrous low mid-range chug from actives.... They do however seem to bridge the divide between high output passives and clear/tight medium output passives.
Now, if you're after something lower output as far as the pick-up goes, I would recommend the Full Shred too - it's crystal clear. For my personal tastes it doesn't have enough midrange crunch - it is very treble orientated (Not JB tooth-pick like, but if you're after a HUGE sound, you won't be able to get it). The Screamin' Demon can work, but I found it to be a bit too hysterically 80's rock sounding, it might be too thin for death metal tones (unless you're after extremely sharp tones with a huge bass boost in the pre-amp).
The D-activator line looks OK but I've not tried them so can't comment.
I would suggest to choose a different neck pick-up though, because from the info that I've read the D-activator neck pickup doesn't seem to have much to offer that you don't already have. If you want the neck to sound like a sweeter and more delicate version but pretty exact copy of the bridge, then I think this would be a good choice. However if you want more 'colour' in the neck pick-up sound, I would advise an Dimarzio Air Norton (fantastic mid rich warm shredders' pickup - pretty much exactly what John Petrucci uses), SD Jazz (more cold but very precise under high gain) or a Dimarzio Humbucker from Hell (if you want to go all Paul Gilbert with a tight colourful tone on neoclassical licks).
Would avoid SD duncan distortion (might be too fat) and JB (would be too shrilly), at least in the bridge.
Finally, a Super Distortion S in the middle could work well, but I think it might also sound like neither this nor that... It might be too trebly to be used to "neck" leads and too bassy for crispy rhythm sounds. I guess it'd work great if you wanted a really sharp bridge pickup and a very smooth neck to have something in between for a more iron maiden-style sound, I guess.... Another option altogether would be to consider a single coil style p-up for the middle to get better clean sounds - if you'd want them, that is!
Hope this helps! I play in an extreme metal band so I tried to write some advice related specifically to that.
Roman
