Weber sidedrafts, as in three two-barrels?

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$.

Then you'll have at least half again that much $ invested in tuning parts, as well as many, many hours of your time.

Also, depending where you read or hear it, Weber is either out of business or just about to go out of business. I don't know what will eventually happen to the availability of those tuning parts. There's a Japanese (?) knockoff of the DGV downdraft available, but I haven't seen anything about performance-oriented carbs.

Bottom line is that it would be much cheaper and simpler to convert your injection to MegaSquirt, if tunability and reliability are issues.