I need to add b200 m3 to my existing chassis of b200 m2s
what vic card or mezzane card should i get?
I wil be doing boot from san
Yes, it will
What do you mean by this "is the VIC 1240 comparable to the M81KR or the 1280?"
M81KR is is only use by the M2 series blades, not the M3 blades. The 1240 is only for M3 series blades and the 1280 is used UCS M2 (B200, B230, B440) and M3 Blades (see documente below).
Note that if this is your first b200 m3 your UCS environment must be running a minimum firmware of 2.0(2) as this is a requirement to for this blade.
Release notes 2.0 (Table 2 Internal Dependencies)
Regarding the VIC card,
You can use the VIC 1240 which will allow you to configure boot san. if you want to increase your bandwidth you can install the Port Expander but note that this is only supported with second generation IOM 220x (see spec sheet below)
Also see table 8 of document below for other supported Mezzanine adapters.
B200 M3 Spec sheet(page 19)