Ignore DIY, in this price bracket (up to $5k) I wouldn't bother with DIY. The choices for a high quality preamp are numerous, but having heard few I'd recommend having a chat with the likes of tyrion, Voltron, and a whole host of others before assuming that the B52 is the best money can buy.
Something like the BAT VK3i springs to mind as costing less and including remote control as an option.