Newbie Autocrosser questions

[michael.leach at lmco.com (Leach, Michael)]

I am going to attend and participate in my first autocross with the Scirocco
on Sunday and I had a few questions.
 
Current car setup. MK2 16v
Bilsteins with H+R springs
16x7.5 rims with 205-45's
I have plenty of mismatched teardrops in the garage along with the tires on
the Passat.  They are all 185-60 14's
 
I am figuring that I will be better off with the teardrops than the 16's.
Should I replace all 4 tires or will changing the fronts be enough?  And
what tire pressure should I run 40-45 lbs?
 
I am also concerned about my Battery in the trunk....other than making sure
it will not move are there any other requirements I should be aware of??
 
I just want to run a few times before I make an investment in tires + rims 
 
thanks for the help.
Michael Leach
MH-60R Integration and Test
Lockheed Martin Federal Systems
Owego, NY 13827
607-751-7542
FAX 751-6198
michael.leach@lmco.com <mailto:michael.leach@lmco.com>