I have to inject something here. First you threw out there 300 HP as if that was the minimum you would take, and I hear that a lot from many people. Mostly young ones. Judging by the poor grammar, and the rose colored glasses and your past cars, I would say your pretty young and very new to Z's. I also think your reality has been very skewed by reading too many magazines. Tuning a computer controlled modern turbo car is NOTHING Like tuning an old carburated inline 6. Other than they are both air pumps, they have little to nothing in common. Now, lets get to business. What are you going to be using the car for? Realistically Is it a daily driver, is it a show car, is it a track rat? This is very important. Second, get 300 HP out of your head. There is nothing magical about that number. Vehicle weight, final drive ratio, good tires, suspension are all ways to make a car faster, that are FAR easier than monster HP to achieve and to live with day to day. Third, make a budget and stick to it. Do not let costs creep up and up in search for a number you will never get. Remember this. Making N/A HP is like running an old muscle car in the quarter mile. It is easy to get it to run 14's, but it gets far more expensive to run 13's and exponentially expensive to run 12's. Same for HP. You can take a stock L24 and get 165 HP out of it with some good parts and tuning, but to get 200 HP gets far more expensive, and to get 250, it is a big step function costing more money. Pick a budget and let the HP fall where it may. Third. The end result may be 220 HP with all your money spent, but keep in mind that true enjoyment comes from having a car that you can turn the key and reliably drive down the road and smile the whole time. It does not take monster HP to do this. Especially in a Z. Good luck, and thanks for your service to our country.