<VV> Helicoil or Time Sert?

[ChiefTAM at aol.com]

I have an oil pan that is leaking, and there appears to be a bolt or two  
that are not holding, probably stripped.  There was a thread back in May or  
so that talked about leaky pans, but I can't seem to find it.  What is  
easier and better (if there is such a thing) to use to repair threads, helicoil  
or Time Sert?  
 
While I'm at it, any benefit to going to an aluminum pan like Clarks over a 
 stock steel?  The aluminum pans are pricey!
 
What is the best gasket to use?
 
What is the best way to keep the oil pan bolts from loosening up after  
driving a while?  I torqued the bolts to the proper torque a short time  ago, 
and most are loosening up, allowing the pan to leak oil.
 
Thanks for the assist.
 
Todd in TX