Hey El
. In my view you don't need an EQ with MP1/2, but some remark the bottom end eq in the MP1 is in the wrong spot (centre freq). Personally I never had an issue with bottom end in my MP1, but each to their own. Also I'm a minimalist, less is better, each gadget brings noise.
There are some fundamentals that are good to stick to with EQ (and any gadget really). The need to stay unity gain so overall level doesn't change from going through them. With EQ that means if you boost a bit then cut a bit, but this can be adjusted for with the EQ's input and out put levels (if it has them). So that's to preserve your gain structure which is the most important.
Where to boost or cut depends on the sound you are going for. Again less (subtle) is better. What about your tone do you want to improve ? Does it need more bottom end ? (80Hz), does it need more sparkle (8KHz). Remember these will change at different volumes, if you are adjusting for low (bed room) levels, do a loudness curve (boost 80Hz, make a nice "smile" curve to a boost at 8KHz with centre of the curve cutting). At volume, add what you want a bit more selectively, e.g. just add some 80Hz to fatten it up.