They had proposed Irbis E for Radar upgrade which is again a PESA but is more powerful than BARS and tracks and engage more enemy fighters than BARS. IAF is interested only in AESA which is still not available. Byelka for Su-57 is still in development and will be available post 2025 only, one of the reason why Su-57 is still under development and not considered a true 5th gen fighter till now apart from the engines.All the more easier to reject their offering then. Go ahead with the rest of the upgrades & test Uttam Mk-2 on MKI as & when it's ready. Where's the issue or confusion ?