Yes, 273 MHz works on both of my wizards.
My older wizard used to go down to 99MHz, but after I took it apart it only goes to 123 MHz.
I have been using your ROM today with SPB Mobile Shell, comparing it with my HTC Kaiser running Android. The wizard is definitely faster. I think it even compares well with the Kaiser running WinMo 6.5.
Next I'll try Manila 2D, to see if it works well.
and RAM is not good.. just 23 MB after SR.
but...CHECK THAT!: http://forum.xda-developers.com/showthread.php?t=602221
btw. do you can upload just packed FOLDER 2 of Manila2D package? i have completed my download limit of internet, so i have speed max. 64 kbps.