its just the swap with build pistons, rods, but not the crank, then also? how much or how big of a bore can you get with the sti block? closed? semi closed?
it is worth kelley blue book value. Then you add on the assumed value that you think some ignorant shmuck will be willing to pay extra for your mods. If you are reasonable, you add a grand to the bluebook and say best offer. If you are an entitled ass you total up the cost of all your mods and labor, subtract 500 dollars and claim you are giving people a good deal. So, expect $8,000 to 36,000 depending on how delusional the seller is.
I go about it something like this (you can call me a nerd if you want to): If the modifications are not documented, value to me = ((.65 * kbb) + (price of mods * .25)). If they are well documented and backed up by a reputable shop, value to me = ((price of mods * .5) + (kbb * .9)). Assuming clean title, avg miles and such. Regardless of what they are asking. Obviously adjustable depending on quality of mod, degree of modification, etc. Definitely not a complete equation, but a good starting template.
Probably less than a stock 2.0, as most folks dont like the idea of someone being into the motor of a vehicle they are paying 8-10K for, expecially if they dont know WHO was in it, and with what supporting mods the car has, tune/ect.