as far as adjustability, look at the nuts on both ends of hte rear tower (Front also for that matter), you spin the bar itself to lengthen/shorten the ends then tighten down the nuts to hold it in place. It just may seem like it's not adjustable cuz in the pic the bars are at their narrowest adjustment.
The holes may make the bars marginally. Tho that's a BIG "may". Similar to the same principal that makes a pipe more structurally strong that a solid cylinder of metal.
for the price, u can't really get much better <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt='
'> I'd say just go for it. Hope this helps.