Hafler XL600 Vs Hafler 9505 Much difference?


Hello all, I am new here and still learning to navigate the website. I have been out of audio for a number of years. I had an old Hafler XL600 years ago and really liked it for the price. I am thinking of getting into audio again and am considering purchasing either an XL600 or the newer Hafler 9505/9500. I have read there have been a lot of improvements in amplifiers in the last decade. Is that true? How much difference is there in the amps I am refering to? Would I notice a difference between the XL600 and the newer amp? I hope to purchase Boston Acoustics VS336 speakers to go with this.
Any info would be helpful.
Thanks
sundriednm
Should have mentioned; those caps are slightly(10%) over the stock uF value, very low ESR and long life. You can further improve your 9505's presentation, with a pair of these(easy to install) FRED bridges: (http://datasheet.octopart.com/VBE17-06N07-IXYS-datasheet-143416.pdf), higher quality binding posts and RCA's, all of which can be gotten from Michael Percy: (http://www.percyaudio.com/Catalog.pdf)
Ok, assume I know nothing about audio, as that appears to be the case. :) What is a FRED bridge?
I'm guessing you didn't check out the link that I provided.
(F)ast (R)ecovery (E)pitaxial (D)iode It's been my
experience, that their being substituted for common bridge
rectifiers, eliminates much grain/noise from gain circuits,
resulting in a more natural presentation. Regarding the
leaving off of the amp's top: I suppose it could be dangerous,
if there are those around that might place their hands in the
amp. I'm not faced with that issue. If I were; I would use
stand-offs(about 1/2") and longer screws to reattach the top.
No, I looked at the link and it didn't mean much to me. I live in the Philippines and my biggest challenge at the moment is finding someone who will repair the Amps using my parts. I went to a chain shop yesterday that was recommended but I have to use their parts. Who knows what they would be.
I appreciate your input. I should be hearing back about a different tech recommendation today.