Not quite the same comparison, but I bought an E91 325i and after less than a year of finding the performance disappointing I replaced it with an E90 330i that was so much better I still have it more than 7 years later. Both were manuals with N52 engines and the difference in performance was significant.
I'd recommend Tony sticks to his guns and waits for a 30i - settling for a 23i would probably only lead to disappointment, or forever wondering "what if"....!
I'd recommend Tony sticks to his guns and waits for a 30i - settling for a 23i would probably only lead to disappointment, or forever wondering "what if"....!