The D-series is best for BUDGET turbo'ing.
Given that you can find most worn D16s for around free to $100.00, they can be fun and inexpensive motors to build.
Granted after you refresh things to the point where the motor is healthy again - a project like this can nickle and dime you to death.
Count on spending at least $1,500usd on machining, internals, water pump, oil pump, timing belt, t-belt tensioner, seals, gaskets, coolant, homemade fabrication and a junkyard turbo.
All said and done, it wouldn't be unusual to spend $3k or so to get everything in order with regards to fueling, drivetrain, engine management and perhaps most importantly tuning.
search google for fjt distributors. Their prices are great for rebuild/turbo internal packages. It'll get you started if you're seriously considering this build. Normally, if you kept things under 220whp, you could likely get away with stock internals, but since you said 300whp... unless you have a really good tuner and a guardian angel, I would advise against trying this.