It is really hard to say honestly, for instance the intercooler you have can be bought for 140 shipped. So first take that into account. Piping, can be had for as cheap as 60 dollars.
I only paid 100 for my complete 3 inch exhuast piping. Motors are one that really does matter the condition, use, miles and the like.
I paid for what was said to be a low mileage engine, only 250 dollars. Still havent comfirmed anything about the motor less that its compression is 150 acroos the board. That said you can get a motor for 250 up to 500.
Transmissions go for about 150-250. So add it up and go from there.
So piecing it together your looking at 600 - 900. I would say start at a 1000, or what you think its worth and go from there. Then just set your bottome line.