If possible, try to import a PSA s1500 or RA Gamma 15 . These subs are $950 and $850 respectively.
These subs are capable of matching and even outperforming the SVS SB13 Ultra.
Both the above subs make use of 15inch driver, however, the PSA sub is just the size of the SB13 (17" cube) and weighs under 35kg.
These subs may be even better than the Value-for-money king: Rythmik E15HP.
If you have friends or relatives returning from US, the PSA sub can be imported through them however, direct purchase may be much complicated and also expensive.
These subs may not be in your price range, but still thought it would be nice to share this information.
It would be great if people in India do group buys for subs like the SEAON, JTR, PSA, RA etc. like those people from Australia.
Wonder if anyone in India even has a Seaton sub (the benchmark sub)!