For 180whp N/A, you should really look into another engine (I factored in the cost issue). With a d-series, even a mini-me, the 150/160whp threshold will be hard to cross without a lot of cash. Also, if you do reach that mark, you'll probably have a very aggressive cam and other things that won't make the car very "streetable". You're better off taking the massive amount of cash you will end up spending and invest in a cheap b-series engine.

If you want 180whp with a turbo, that won't be very hard at all. Just get some decent engine management, and you're good to go.