I would get an amp - it would improve the sound noticeably - but I would go with a different one than the Marantz PM5003. By the way, you can get one for $449 on amazon.com
I would consider getting it used here at the audiogon.com
You will end up with more quality for the buck.
Take a look at these :
http://www.audiogon.com/cgi-bin/cls.pl?intatran&1256328090&/Onkyo-A-9555
http://www.audiogon.com/cgi-bin/cls.pl?intatran&1256065250&/Music-Hall-a25.2
http://cgi.ebay.com/Acurus-DIA-100-direct-input-integrated-amp-NO-RESERVE_W0QQitemZ180385071434QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item29ffc9c14a&_trksid=p3286.c0.m14
These have more power than the Marantz, and would sound better in my humble opinion. I would recommend the Acurus especially.
Your ears will thank you if you upgrade the amp...
I would consider getting it used here at the audiogon.com
You will end up with more quality for the buck.
Take a look at these :
http://www.audiogon.com/cgi-bin/cls.pl?intatran&1256328090&/Onkyo-A-9555
http://www.audiogon.com/cgi-bin/cls.pl?intatran&1256065250&/Music-Hall-a25.2
http://cgi.ebay.com/Acurus-DIA-100-direct-input-integrated-amp-NO-RESERVE_W0QQitemZ180385071434QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item29ffc9c14a&_trksid=p3286.c0.m14
These have more power than the Marantz, and would sound better in my humble opinion. I would recommend the Acurus especially.
Your ears will thank you if you upgrade the amp...