Hmm... I believe it is 250 for a single stat, 510 overall. One stat can only have 250 until it peaks, if i am right.
Sorry...
Cap is 255 for a single stat but it gets divided by 4 for the calculation to go onto your current stat so there is no point in having more than 252 in any single stat. the total max is 510.
Heres the calculation if you dun believe me ...
(((IV+2*Base+(EV/4))*Level/100)+5)*Nature Modifier
Trust me, i coded it myself...
LINK
edit:
I dont think there is an "alternate form" of MewTwo to start off with... never mind a "New" one...
It could though ( as i think this is what you meant ) be part of the Mew Family.
If you remember correctly, MewTwo was made by Giovanni (i think him?) In a lab, from the DNA of Mew, therefor, he is one of a kind,, unless somehow he had some "Super Fun Kinky Time" with a poor little mew and made a MewOneAndAHalf
