Ok...I have a Marshall 1960 straight cab with the stock Celestion GT-75's I think. I want to put 4 new Eminence speakers in(2 different types) in an X Pattern. Question: I run my single cab in stereo mode....right now with stock speakers I use the 8 ohm output on amp. If I buy 2 new Eminence speakers for each side should I get 8 ohm speakers? I thought in stereo these two 8 ohm speakers, in series, would add to 16 ohms per side? If so are the stock Celestions 4 ohms a piece and add up to 8 ohms in series? Please help! Also...what 2 Eminence speakers should I mix? I play in a cover band that does everything from Creed to Van Halen to Maroon 5....need clean and heavy distortion. I use a Mesa power 2:90 with 90 watts per side. So what speakers what ohms?? Can you mix speaker wattage...say a 30 watt with a 150 watter? Thanks!