Hmm... I've been gone a long time but it seems, at least to me, there is a question that needs to be addressed. If Christ Jesus knew no sin and therefore was righteous, and if sin (just a single sin) separates us from God due to His Justness and Holiness - What does that mean when the scriptures state "... He was made sin, who knew no sin..."
I'll try to be brief but I an not very good at brevity.
I do not disagree it was the love of God that set forth The Sacrifice for the propitiation for His people. But I also must acknowledge that the sacrifice is specific to the law of God where by justice must be satisfied against both the transgression and the transgressor. This speaks directly to the justice and holiness of God in which the punishment against sin (the action) and the one who committed it, must be carried out and that, without mercy. (Heb 10:28) Don't know about you gentlemen but 'without mercy' means the judgement of God and that without mixture as spoke of in the book of The Revelation. We call that wrath!
If scripture is true (and we agree it is) then when Christ was 'made sin' or became sin, - then what does this speak to regarding His righteousness. He did not become a sinner but became the very embodiment of sin and the substitute/replacement for those who do them, and therefore (in that place) must be judged by the Law of God. When God gives the eternal judgement on sin, it is a judgement that lasts without end - as stated, eternal. When God judged Christ as sin, the law was fulfilled and God was satisfied both with the requirements of the Law, and the sacrifice. It pleased God to crush Christ, for the sake of Law (His righteousness, Justice, and Holiness) - yet - also for us (His love, mercy, and grace).
It cannot be denied, in my opinion, Penal Substitution unless we take away the law and the requirements and reasons therein. For if Christ "...'became' or 'was made' sin for us..." this must be dealt with, and it cannot be done so without the Penal Substitution.