The Ti was a really nice woofer, but pretty high inductance and really didn't play upper bass that cleanly. That is not to say the R's are the best at it either, but they have some good shorting and significantly lower Le.
The Ti's with their excessive stroke were low end monsters back in the day .. but most here haven't heard them compared to what is out today, so the "impression" of the Ti still remains, but the actual performance isn't worth the old price relative to today's woofers.
A pair of most any decent 12" woofers is going to outdo the Ti if they work well in your enclosure, which the Type R will. Do you know if you have the older R's or new ones? Is the logo in the center or the bottom of the cone?