Sad news, correct replacement for these Jaguars is Tejas Mk 1.
THERE SHOULD BE EQUAL ONE TO ONE REPLACEMENT OF Jaguars by Tejas.
I am going to tweet Both PM and RM
Payload wise, yes. Range and endurance wise, not exactly. The Jaguar has a longer range and greater endurance than the Tejas Mk1/Mk1A, at least without refuellers and we all know how short the IAF is on refuellers.
the Tejas has somewhat adequate numbers in the pipeline for now, if the Mk1A order comes through soon so that the line is not idle. But, the Medium Weight Fighter is the one that will be critical. Being sized around the Mirage-2000, it is the ideal size for a single seater and will be a far better replacement for the Jaguar.
The issue at hand is the HAL assembly line that is likely to go idle unless new orders for the Su-30MKI are placed. Placing any new Tejas orders will not bring any additional fighters out since HAL already has its hands full and hasn't yet managed to ramp up the production to 24 per annum.
What the IAF is contemplating is to basically buy possibly a couple squadrons more of the MKI and not invest in the Jaguar upgrade. When the MWF and Rafale/MMRCA lines begin churning out fighters, that time they will place additional orders on those to replace the Jaguar fleet entirely. This may lead to the Jaguar being retired a little earlier than was planned if the Jaguar re-engining had gone through.
TBH, where the Jaguar is a good airplane, with few aerodynamic vices for the role it was designed for (low level penetration and interdiction), even back in the day when it was inducted, it was known as an under-powered airplane. RAF pilots used to joke that it could only take off fully loaded thanks to the curvature of the earth. Even with avionics upgrades, it is still an airplane designed for a single role, requiring fighter escorts to protect it from enemy fighters. And if the cost of the re-engining was truly as high as 2 or 2.5 Jags = 1 Rafale or Su-30MKI, then its a no-brainer to ditch the re-engining and go for new air frames. They'll have 40 years of life and being fully multi-role fighters, are way more useful than re-engined Jags.