If you want to get rid of specific DriverPacks (for instance 3rd party DriverPack), just rerun BASE as OverFlow has said and deselect them, then re-slipstream.
This procedure also works for updating a source with the latest DriverPacks.
As slipstreaming the DriverPacks is supposed to be the final step before ISO creation, this shouldn't break anything (I have done it myself several times always with success).
I would not suggest manually removing specific components until you really know what you are doing.
It is also more time-consuming than re-slipstreaming so you gain nothing by it.
If you really need to fit it on CD (I was using that myself until half a year ago or so), there's a couple of steps that can help you:
Firstly, I recommend using nLite to slim down the source.
There's a lot of stuff you never need (really!) and some more you can easily do without.
MSN Explorer, WMP (if you use another player), all the languages and KB layouts, the intro movie, the search dog and whatnot.
If you want to, I can post my ls.INI so you can use that as a template for your own.
Secondly, if you only use the official DriverPacks (or rather not the Printer 3rd party DriverPack), that should not use too much space.
Thirdly, if you use Nero to burn the ISO, there's an option to enable short leadout, that saces about 12 MB of space, definately vital for a CD edition.
Fourthly, if really needed, there's 800 MB CD-Rs and even 900 MB (though the latter might be incompatible with some drives).
Unfortunately, those are not available as RWs from what I know (if you spot these, please tell me! ) so you will need to do extensive testing in either a VM or use a DVD±RW and a system with a proper drive for testing, then brun the final version on the CD-R.