I own a BC Rich and the wood is not made from mahogany and I was just wondering if these pickups would still sound good...I have heard that non mahogany will make it sound brittle and trebly.

if these pickups wont give me the tone im after (which is a heavy rhythm tone, and smooth lead and clean tone)

then which pickups should i consider trying that will suit my guitar?
Is it nato? In that case, it's just the same as mahogany.

Second, EMG pickups sounds more or less the same in any wood, so I don't think there is a problem.
We should start calling it "The Fact of Evolution", theory, even though correct, does not work with the ignorant..
As Blargaha said EMG's will sound basically the same in any guitar so you'll be fine. Maybe worth ensuring you do want EMG's first, like Dimarzio or Bare Knuckle
Current Gear
Washburn WI66 Pro //
Ibanez Prestige SA1260 //
Schecter C1 Blackjack //
Fernandes Ravelle Elite //
Wahburn HB35 Semi-Hollowbody
Blackstar HT40
Agreed with Blargaha. I have one in my Custom and I use to have an LTD MH-301 Neck Through Mahogany, My Custom is an Alder body with an EMG 81 in the bridge (Does not have a neck pickup, just routed for the bridge pickup only) for on the fly Guitar Switching and it saves my back a little after some hardcore gigging with my Les Paul, but they both sounded the same, I was dissappointed so I sold my LTD and bought more parts then I can assemble!
Gibson Les Paul Custom (Aged White)
Custom Kramer Baretta
Custom Fender Strat
Epiphone Black Beauty
Epiphone AJ
Marshall JCM900 4201
Blackheart Little Giant
MXR Dist. +
MXR Six Band EQ
MXR Phase 90
EMG 81/85 combos get put in Basswood and Alder all the time... and still sound the same.
Not trying to be annoying, but I disagree with the "sounds the same in anything comments";
I had the 81/85 set in my SG and it sounded pretty decent with either in the bridge or neck. When I moved them to my Cort, the 81 sounded really thin and kinda weak without the lows from the mahogany. 85 in the bridge works better in basswood for me.

EDIT: Oops, bit late. Anyway, glad you're happy
Obligatory gear list
Ibanez SZ4020 w/BKP Miracle Man set
Cort X-11 w/EMG 85+81
Tanglewood TSB58 HB w/BKP Nailbomb & Cold Sweat
Epiphone SG Prophecy w/Seymour Duncan/Ibz
Indie Swamp 4
Ibanez BTB 775 PB
Engl Screamer 50
Last edited by lyonk55 at Dec 15, 2011,
The best analogy ive heard for actives vs passive pickups is this:

Active pickups add most of the colour before the guitar hits the amp, while passive pickups let the guitar wood and the rest of the guitar come through before the signal hitsthe amp.

And yes thats not an analogy but still its the best way ive heard to phrase it.

Emgs and actives will sound better in better wuality gitars but for the most part an active pickups tone comes from its internal preamp which creates the consistency