lexphin,
I have been using copper beading cones inserted into copper end caps. The former are really hard to come by lately. You need to do a Google search. The latter can be had on Ebay. Since I have never used SR's HFTs I cannot comment on how they compare. All I can say is that if you find the right positioning the results can be very impressive with a DIY version of SR's HFTs. I have over 70 in my system -- total cost about $70 vs. $4,200 for 70 SR HFTs. How's that for getting a bang for your audio buck?