I'd say any additions to the initrd will slow things down (which might not be noticeable if they are just a few small files). Likewise any extensions integrated into the ISO image will cost time for their loop-mounted installation (if they are onboot). As the term remastering is used for both things you might want to read another
post where I tried to spell out the difference.
So, NO I don't think remastering will give you any faster boot times. TC is anyway the fastes booting Linux 2.6 system I know of. Well, unless you thought of actually reducing the inird. But then I' love to know what you plan to strip off. If you don't need an X server you should use MicroCore, which then does not need to extract the additional files. But in my perception this is not a huge amount of time a saved.
BTW, I remember someone once did an analysis of the TC boot times, unfortunately I can't find it right now, but IIRC there was not much "fat" that could be cut out.