[Freesurfer] question about fsaverage vs. my subjects average

Hi

I have 3 questions:

1) Does it affect the stats (or does it just affect the display) if I use the fsaverage brain vs. the average of my subjects brains when running mris_preproc or when simulating the cluster statistics using mri_glmfit-sim?

2) I downloaded the simulations for multiple comparisons correction mult-comp_cor.tar.gz. (which I later realized were also in freesurfer/average/mult-comp-cor). How do I apply the simulations to my data (assuming I used fsaverage)? It doesn't really say on the group analysis page how to apply the *.cdf file (or I missed it).

3) I see on the list that mention is made of a possible symmetric template, and there is an fsaverage-sym directory in the file I downloaded. Is this template available?

Thanks, Darren