you have another option, which might be cheaper, depends on whether you have access to actual weber carbs, actual weber carbs that maybe need a rebuild and can be had cheaply.
you can buy two of these adapters, which mount under weber carbs, and allow you to use the webers as throttle bodies, with the injectors mounted in the adapters. the adapters sell for 250usd for 4, plus you'd need the 4 webers, 8 injectors...but basically you'd be running an actual weber setup, just with efi control.
can be bought from here...
http://stores.ebay.com/CONVERSION-COMPONENTS
hth