Hawk have pretty much dominated the 289 replica market for years and have refined their product with lots of development.
There's a couple of early Hawk 289s around here that run on MGB suspension as per his original design. His later cars have gone with Jaguar suspension but he's tried to retain the 3" tube chassis as per the original.
Good choice with the 48IDFs. Will be fun to set up. Much better than a Holley in a turkey pan like the 427 copies.
Lots of 289 info here - http://www.the289register.com/
or there's the UK Cobra Replica Club.
From the look of that last photo, am I right in guessing you are building it as LHD?
Keep us posted.