You are fortunate now in that you have the option of buying an IAG longblock off the shelf, which was not a standard offering when I started my journey. If I had to do it all over again now I would just buy one of those longblocks, unless you have plans to race the car and know a well respected builder specializing in that discipline (pros and cons but my understanding is racers prefer to go the sleeved route and use a seasoned engine for that purpose). For a daily the IAG is hard to beat and has a proven track record.
However, regardless what you choose engine wise, you will still need all the supporting mods, which will easily double the cost of the long block. 20K is a conservative number (if you want to do it right and have longevity) and you probably need to plan for a minimum 20% variance, depending on choices. The thread referenced above is a good starting point. Also search for user1029’s thread related to progression; it will help you plan your path. I wish I had seen that before I started my journey as it would have made a huge difference with some of my early choices.
Last thing I would say is make sure you and your tuner is 100% on the same page and that you verify the recommendations they give for the build. When I started my path my direction for my builder was an end goal of a comfortable 550-600 whp. They built me a 500whp rated engine and did not explain all the additional mods I would need to get to where I wanted to be. At the time I did not know a fraction of what I know now (and I am still no expert by any means), but I naively trusted we were on the same page. The engine they built me cost the same (or very close to) an IAG long block rated in excess of my original end goals and I would not have had to wait such a long time for the build to be completed either. Some of the supporting mods they installed were way underrated, which resulted in “double-buys” (e.g., 1000cc injectors that I had to replace with 1700’s when I did the fuel rails, a different fuel pump, etc.)
If all this is way above what you originally thought, then do it incrementally (using user’s thread as a guide).