Why don't you go drive a car with nitrous, one with a s/c, and one with a turbo. All in the 400whp range and see what you like.
I've had or done every one of those combos myself, and know each has strengths and weaknesses. Nitrous is filling bottles, yea $40 is not the end of the world, but you ad that with a track entry, and in the shot you get into finals and make more than 4 rounds you will need another fill. That adds to a $100 night.
The turbo will be a pain to install, a bad engineered kit will dump a ton of heat around all sorts of stuff that you may have short/long term issues with. Tuning is typicaly not easy to do, and you absolutely must find a tuner that knows tuning turbo cars.
The s/c is by far easiest to install and can make just as much power. The kits are tried and true, can tunes work relatively well, and you can get a new kit with everything and be done in a weekend.
400HP is 400HP whether it's nitrous or boost. You can get there multiple ways, but if you win a race with nitrous, s/c, or turbo, who cares, you win. Why not go the easiest way, and where you can get the most support if you have issues? I would KB that biothch in a second. A buddy had a 04 GT, he got the KB flowzilla setup with fuel, tune, injectors. No other mod than an exhaust he was 400+/400+ on hp/tq, and ran high 12s at 5280ft. And he was by far no mechanic genius, installed it himself in a weekend.