Are you a teen/child/kid ? Depending on your weight and skills, a Formula is not always mandatory...
As for the Phantom Race 380 cm sheer size, it barely fits inside a VW T4 van without a board bag. You'll need either a long-bed van to store it inside her board bag or strap her on top roof's racks for transportation.
What minimal wind speed are you considering to go out sailing ? Phantom Race is great for non-planing as well as planing conditions in 1 single package. If you'll pick up a large iSonic or Futura or Formula for planing conditions and wants to go sailing in non-planing conditions, you'll need a second board (Serenity?).
Any wind stronger than 15 knots on your lake ? Have you got another smaller board and rig as well for strong wind or is it going to be your 1 board + 1 rig package ?
Please, tell us more about yourself and your unmet needs.