Ah, the M-04M.. heheh.. yeah, it can be a handful if it's not set right, but it's my favourite to race indoors..
The problem is likely your tires in the rear.. unlike the M03 where you can put the crappy stock tires in front and drag the rest of the car behind no problem, the M-04 needs high-grip rear tires like the S-Grip or Type A with the Dark-grey firm inserts..
"Soft" is a relative term, and I'm not sure what spring rate greens are, but if you have Tamiya reds (or the fluorescent reds) put them in the rear.
Be sure to sauce the whole surface of the rear tires really good with traction compound..
If you find the rear "jumpy" when accelerating, it's likely from the friction shocks.. try putting a set of your M-03's oil shocks in the rear, that'll dampen the spring action and keep the tire planted on the ground.. The fronts you can pretty well keep friction, as I have it set pretty solid, there isn't much spring action at all..
I have a setup I always use, never fails me.. end up posting a few times a year to keep it fresh for those interested in this much-maligned car..
M-04M Carpet Setup
Front:
TRF Short White springs
TRF Shocks, 80 wt oil, 2-hole pistons, 2 o-rings, no rebound
S-Grips, moulded insert (hard to find), 1/3 traction compound on inside
Sway bar
Rear:
Short Fluorescent Red springs
TRF Shocks, 60 wt oil, 2-hole pistons, 3 o-rings, no rebound
Type A's, firm foam insert strip, full traction compound
5-6mm ride height all around
It's a very stiff setup in the front, and runs like a touring car.. no body roll for quick transitions, and at the same time I can run through the whole track full-throttle without flipping. If you need more steering, widen the strip of compound in the front.
Get the 2-degree rear uprights if you can, or just upgrade to the lightweight "M03M" set, it has 2 degrees already, and is very nimble.
Put the receiver and speedo on the sides like saddlebags, keeps the COG way low.
I use the Alfa body for TCS, and the HPI Miata for the other races.. love the rear wing..
That's the basis of the setup, the rest is optional.. aluminum hexes, rear universals, carbon gearshafts, TA03 Ball Diff w/ lightweight plates, aluminum screws with a few Ti in spots, but it's not that necessary.