That won't be a problem much imo, given at this point this JV is sort of a stock option for them else they would have raised some concern when we went on with making the core items that were Rus responsibility ie seeker fuel ramjet etc. They will take 50% of the profit generated and that's it.Political. The IP is co-owned which means the Russians will have to sign-off on it, and they are not going to. If we want to use our own ramjet, it's going to have to be on new Indian designs, like LRLACM and STAR. We can always design a Brahmos++ with a 500 kg warhead, if necessary.
By scaling up I mean reorganising the old Brahmos internally to hold enough fuel for 800km or more ranges without much redsign of the airframe. I don't think they change anything in the motor itself since BAPL place order for the full motor as high lead time part and fit in without any mod. This will be possible with the new ramjet they are making, easier to augment fuel feed flow and flow rate etc.At 6m long, it's already at the limit of ground clearance for takeoff and landing when on wings. Increasing the length will push it out of the inventory of most jets. So the best they can do is play around with internal layout, smaller electronics, better fuel quality, and motor efficiency if they want more range.