Generally if you talk to anyone knowledgable in car audio and you will get some degree of consensus in that the front stage (ie. your front speakers) are the most important part of your system.
Spend the most amount of money you can afford in getting the best front splits possible. Everyone's budget varies but the point is get the best YOU CAN AFFORD. Next most important is the head unit, then amp, then sub. As mentioned above, have a look at the car audio australia website and do some reading before you spend any more money/time. Check out the beginners section and frequently asked questions areas.
IF you don't take the time to do some reading/research and expect people to give you the info on a platter without making any effort on your wn behalf, then expect don't expect too much valuable advice in return. If however you take the time to do some reading and develop some knowledge, then people are more willing to lend a hand. I'm always happy to help as everyone has to start somewhere.
I had a pair of the glass action kickpanels and they will suffice for a basic system with 6 1/2 in splits. Once you start to get more involed in car audio and upgrade your components (eg. like my splits which cost ~$1000 for the pair), you will want a sealed kick panel. I took the initiative and constructed my own sealed enclosures to maximise efficiency and volume to get the best from the 6 1/2 Dynaudio woofers, see here for "how-to":
http://www.manxgallery.org/gallery/album221
Apart from my sub box (which houses one 12in eclipse sub that is more than enough), the kick panels were only my second attempt at fibreglassing so don't think only the pros can do it. In terms of amp, again it depends on what you are trying to achieve in the short term vs long term. I run a 4 channel amp of which two channels are bridged for the sub, then the remaining two channels are devoted to the splits. Down the track I may add a monoblock for the sub which will dedicate the 4 channel solely to the front splits (ie. two channels each bridged for left and right splits). Hence why you have to think down the track as well.
Alan
