I say build you motor you have now. Going for a swap is not necessary, specially when you can just build it better than any stock motor. Invest into parts to build your motor. Once you get everything set up for a rebuild. Take it to the shop and have them build your motor. Once all is done, what you can think about next is the turbo size you want. That right there will give you the numbers you want easy. You can build your st185 motor and slap in a 20b or ct27 for simplicity and boost it higher for your power goals. Your motor will be able to handle the extra abuse because of the rebuilt motor.
Lets say you wanted to go with a swap.
st205 would be ideal. 2k - 3k+ for the motor depending where you get it and if its a front clip or not.
245/55hp.
If you can't wire it up yourself your looking at about 600+ to have it done prefessionaly.
st205 at 17-19psi 3" exhaust will grant you about 300AWHP from what I was told.
Its pretty much preference. Do you want a swap motor and eventually build that or do you want to just build what you have now.
Or what you can also do it get a st205 head and put it on your block. take the st205 oil pan set up for better convenience.
If I lost you I apologize. I ain't that good at explaining things on paper. Better at it in person