Nope, really no way around the rule unless you do a few track days that prove that you can handle the car at high speeds. I had the same problem when I started. I just ran without a turbo (literally just ran intake piping past the turbo) for my first race. Then realized it was just as much fun in Open Light, and the competition was much closer that I swapped in an NA engine and sold the EJ22T.
Open Light is quickly turning into a very very fun and competitive class. In my region we have 4 drivers or so in very similarly prepped cars. We are all within seconds of each other on the stages, makes for some incredibly close racing that makes us push ourselves to be faster. Way better than being in Open class and having to gauge yourself against all the WRX's and STI's who will obliterate you on the straights and usually have more experience, so will also kill you in the corners.
Rallycross... while a great way to get into the sport, will mean nothing once you get on stage... trust me. I did rallycross for 3 years and thought I was hot shit, then I got on stage and holyyyyy crap. All of a sudden sliding around cones in 1st and 2nd gear in a grass field was just kiddy business. Rallycross cannot prepare you for how to react when the car steps out on you on pea gravel at 80mph heading towards a tree or a deep ditch.
That being said. The Legacy is a FANTASTIC car for a first timer. The longer wheelbase makes it much more stable at high speeds than the Impreza. Plus all the impreza bits (except the driveshaft) fit the Legacy. Once lightened up, the leggy is also just about the same weight as the Impreza. It's a win-win situation. I am very happy with mine.
