So im looking at a used F275

It has the Fox float ctd on it but want to go coil (dhx)

I cant seem to find the shock size. I asked the guy selling the bike and he told me 7.5 i2i ? Is this correct ? Do you need specific spring rates for Foes with all their 2 to 1 mojo stuff ??

Im 180lbs so im thinking 400 spring rate

Any help would be GREATLY appreciated !