Just as a relatively cheap experiment, consider modding the crossovers to improve the sound of your rti28's. Dennis Murphy, a well regarded crossover designer and musician has an article on doing this inexpensively (http://murphyblaster.com/content.php?f=RTi28.html).
I've got the parts and will try it on my spare rti28's.
I've got the parts and will try it on my spare rti28's.