Woofer replacement for Infinity Reference 2000.5 Woofer

Hello Folks,
I recently acquired a pair of Infinity Reference 2000.5 Floorstanders for a silly price ($20). They are a two way system with a wave-guided soft dome tweeter and a 6.5 mid bass driver. The speakers are specced to have a low-freq response to 38hz at -3dB. I got these cheap because they came without the woofers. I mainly bought these speakers for their cabinets as this will be a good DIY opportunity.
I contacted Infinity to query the price of replacement woofers and they quoted me $120 each (!). If I am going to pay that much, I figured I might as well get a high quality replacement.
In order to find a decent replacement woofer, I figured I probably want the Thiele/Small parameters of the original woofers so I can use them as a starting point for my search. . So my question to you folks is this..
1. Does anyone have the T/S params of these woofers? Part number 333235-001. I did contact Infinity and they sent me the spec sheet which I have screen captured below and all I got out of them was the nominal impendence (5.6 ohms).
2. I also think this is a good opportunity to fit a pair of reference quality mid-bass/woofer to these cabinets to build a pair of stellar small floor standers. Can anyone recommend an affordable 6, 6.5 inch or 7 inch woofer that will work well in a largish reflex cabinet like this one? This cabinet has a volume of 32 litres or 1.13 cubic feet. I am going to modify the cutout anyway so cutout dimensions are not a concern. I do realize that the crossover impedes my chances of finding a woofer that exactly matches the combination of crossover and cabinet but I figure I will get a decent match as long as the nominal impedence stays around 6 ohms (Please feel free to smack down my naive assumption).
Any pointers will be appreciated on my first DIY project.