Adding an amp on the OEM radio?

[wmzda5]

I recently found this on ebay. What do you guys think? Im planning on changing the speakers and adding an amp and subs, dont plan on changing HU for now.

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=160260290593&ssPageName=STRK:MEWAX:IT#ht_4378wt_1167