You have been scammed with the price, I bought a Type X in pristine condition for about 8000 if I'm not mistaken, but outside of that, it's a very good project, I agree with what skip said, although there are several alternatives, here are the that I recommend, from the most economical to the most expensive.

- SR20DET: Easy to install, and very economical in ebay are for 3500 dollars (I have placed this option first although the following two are cheaper, because it is the easiest to install)

- 2UZ-FE: Toyota V8 engine, they are very cheap but they are more complicated to install, but it can be a good base, I have already installed one in an s13 and it is somewhat complicated, but also not very difficult, they are from 1000 dollars

VQ35DE: The motor of the 350z, is a good option for a project, and they are not expensive, they are from 2500 dollars

- K-Series / F-Series: These types of engines are quite reliable, they are high rpm engines, and since they are N / A engines, they are a very good base and are not at their limit, so they can be modified a lot, although the K-Series are fwd, so you would have to change the box, but the f series are already rwd.

The k-series are from 1000 dollars, but with high mileage, above 3000 dollars there are less mileage and with all their pates ready, and the f series are from 4000 dollars, they are already rwd, so there will be no convert it

- 1JZ-GTE / 2JZ-GTE: They are quite more expensive than the previous ones, but they are highly recommended, The 1jz-gte and the 2jz-gte that are vvti are a little more economical because they are less desired by the enthusiasts (because the 2jz -gte no vvti hold more than 900hp with stock internals, but the vvti hold 500-550)

The 1jz-gte are from 4000 dollars with manual gearbox, and the 2jz-gte are from 3000 with automatic box of an aristo, but the manuals are more expensive, I recommend you buy the automatic and place a box of 5 speeds of a 2jz-gte, it's cheaper than buying the 6-speed

- RB20DET / RB25DET / RB26DETT: This is one of the most expensive options, but it is not for much either, The rb20det can be a very good option and it is not as expensive, like the rb25, but the rb26 is very complicated to deal with because it's awd with a very complex system, and converting it to rwd is fucked up, so you'll have to buy an already converted one, which is even more expensive
The rb20 are around 2500 dollars, the rb25 are between 3500 dollars and 5000 dollars, and the rb26dett are from 6500 dollars already converted to rwd

LS: It is a very popular option in usa, although in Japan they are more expensive, they are for about 8000 dollars or more, but you already get a v8 engine with 505 hp factory, rwd, it is a good option

VR38DETT: The most expensive and complicated option, but if you want to stick with it, do it, the vr38dett is a twin turbo v6 engine with more than 400hp, with integral traction, it is the engine of the Nissan GTR R35, they are from 15000 V $, I would not recommend it, but if you prefer, go for it!