This seems like a good jumping off place for the discussion to continue.I think one of the problems that bedevil discussions on PSA is the idea that God pours out His wrath upon the Lord Jesus Christ. On the contrary, it is God Himself, in the Person of Christ who is taking our sins upon Himself (c.f. Acts of the Apostles 20:28) and paying the penalty for them, thus satisfying His own justice. Christ is made sin (2 Corinthians 5:21) and God the Father punishes sin in Christ. The wrath is not towards Christ but towards sin.
One last point: if Christ has not paid the penalty for my sins in full, nothing is more certain than that I shall have to pay it myself. Otherwise how is God going to be 'just, and the justifier of the one who believes in Jesus' (Romans 3:26)? How is He going to be 'faithful and just to forgive us our sins and to cleanse us from all unrighteousness' (1 John 1:9)?
I closed the previous thread as it was approaching an end and I believe there would not be sufficient time for members to address or unpack what was introduced.
(@Martin Marprelate , I'm using the above part of your post as it does introduce some legitimate concerns others have had with Penal Substitution Theory. I'm not directly addressing you, but opening discussion for those who are willing to participate).