Thanks !
Actually I found that the MXR sounds better when combined with an amp/cab than when used as a DI.
For this kind of sound, I always have a clean track (amp or DI or both) and a distorded one. I generally highpass the distorded one @ around 800 Hz, and lowpass around 2k. Sometimes what you need is to distort the low mids to get more fatness (around 400-500 hz), then I highpass around 500 or 600. It really depends on how the guitars sound, if they have a lot of body then you have to lower the low mids and scoop more in this area, if the guitars are thinner you can go for more low midrange in the bass. The aim is to obtain that "glue".