Welcome to ETSG! P 90 pickups were invented in like 1945... I don't think they've been out of production since. They have their own area... they don't sound like anything else, and they have a lot of fans. I managed to do without a P-90 guitar for a long time, but when I got the itch, it became irresistible... Lots of great music has been made with them. Derek Trucks could inspire anybody IMHO. The man's a master of the slide guitar and his SG tone can bring tears to my eyes and chills to my spine. He plays hum buckers every time I've seen him on video. So his tone is not P-90 tone. He seems to play very clean most of the time. But big stars like him travel with their own sound crew, so they may look like they keep it simple, but you don't know what the crew is doing to the tone backstage. I believe that P-90 p'ups can be used for almost any style. Rock an roll, Country, Blues, Jazz... all these genres can be played on a P-90 guitar, just as they all can be played on a Telecaster. OR on an SG with Humbuckers, or Minis. The pickups can do anything their owner is capable of. Except maybe Eastern European Heavy Metal, or some other extreme styles. There are instruments designed just for these genres, of course. Pointy ones with seven strings... Anyway, good luck. I wouldn't categorize the P-90s as 'brighter" sounding than hum buckers. I've heard Epi SGs described as darker sounding than Gibsons, but all that sounds like EQ to me, adjust yours to taste. Anyway, the P-90 sound is somewhat more gritty than the smooth and elegant Humbucker tone.... to my ear. It's very rock an roll, it's very bluesy... it's very honky tonk if you're a country fan. It's rockabilly, it's boogie woogie... and it's also cool jazz. Now that I've said all that, let me make one more radical suggestion: Keep your G-400 the way it is and get another Epi SG with P-90s off the used market. The cost of a pair of SD pickups and the cost of a used Epiphone are not too far apart. I'd buy a guitar with real P-90s in it, instead of installing the SD p'ups. Then you have two SGs that don't sound the same, and you use them for different songs and styles. Tune one to standard, and tune the other to DADF#AD or DADF#CD or open G or some other tuning that fits your vocal range. Here's the P-90 guitar I ended up with after my quest was achieved: an Epi ES-339 P-90 Pro An arch top guitar with real balls.