After doing this swap myself I submit that it would be best to think about only the most basic of requirements to complete the swap, then once you have a parts list for the necessary components then see where you are at from a cost standpoint.
I haven't kept a running tally of expenses for the swap because quite frankly I don't want to know what it has actually cost me
but it's alot I know that much.
I know my advised aproach goes against what I did myself but context matters and at the time I had no real budget constraints, so I just threw caution to the wind and did what I had to do, fortunately I didn't waste very much money making mistakes.
For you though I would recommend benifiting from my experience and allowing me to help you do this the most efficient way possible and avoid the complications I had.