After buying my Epiphone LP Special P90, I decided to upgrade the Pick Ups because the Epiphone PUP's were a bit muddy. A friend of mine recommended the Seymour Duncan SP90's, but which ones? After researching the Duncan Website I decided on the SP90-1N Vintage at the neck and the "hot" Custom SP90-3 at the bridge (other review) for maximum flexibility.
The fitting of the pickup in my Epiphone was absolutely no problem, just had to do a bit of re-wiring and if you are handy with a soldering-iron you should have no trouble at all.
The sound in my Epiphone at the neck is typical "Bluesy" with a lot of power (although rated at low output), and really blows the stock Epiphone PUP's away, not the slightest sigh of muddiness and really open:-). If you need a good P90 Upgrade then this is for you.
Cheers