Turbocharging a bigger MaxNC

Folks, need advice!
Have a MaxNC that has extended x axis table (600mm or 24"), still using
1/4-20 rod.

Now feel the need for speed, and the routes i see are:
a) software stay with MaxNC, get a phase to step and direction adaptor,
and fit step and direction drivers e.g. Gecko
b) software (still in DOS and freebie if possible), s+d drivers as above
c) Master 5 from Art, (windoze), s+d drivers
d) make the jump to EMC, and s+d drivers (open loop initially, then go
for closed loop steppers)

Without starting a flame, it it possible to get some advice on which way
to go.

Mechanical bits will be a scaled up version of a MaxNC, using an angle
grinder motor (200 to 11000 RPM) for Spindle. Have done over 1000 hours
on one already, with no problems, will admit the carbon brushes do spark
a bit.
What i use it for is organic shapes, most of my work is surface
modelling, i do mainly formers for dipping latex balloons, using HDPE,
no metal work, but would like to go for 7075 T6 for motorsport
components if possible.
To give some better ideas of the way i abuse the current machine, some
programs are over 4 MB without line numbers and longest duration was
over 52 hours continuous machining, just tidied up with a industrial vac
cleaner every few hours. Main reason it is soo long is that i use same
tool for roughing and finishing pass, a bit of a compromise, but beggars
cannot be choosers! Anybody got a solution for economy ATC????

Have access to good CAD/CAM at work, like Visi, Mech Desktop 3,
hyperMill and SolidEdge, so no issues at that end.

Thanks to all on the list for the excellent advice that passes back and
forth.

john