Aftermarket Protection

[FriendlyFire]

Hi,
When I purchased my new M3 5 door I declined any options such as underbody protection and fabric protection because
a) these options seemed overpriced at the dealer
b) it was not clear to me that it was necessary to buy these options.

Since then I took my old car to a detailer to get it ready to sell. This guy offers a full protection package that includes underbody protection, paint protection, fabric protection, and rust protection. The price is reasonable and he seems to me to be a reputable business man. He is trying very hard to get me to bring my new baby in for the full treatment, possibly because he really believes it is in my best interest. Or maybe he is just looking for a few more bucks... ?

so I turn to you my friends...

is it a good idea? is it necessary? Is there any danger of invalidating the warranty with this type of treatment?

oh yeah, I have little kids who seem to enjoy spilling stuff in the back...

thanks
p.s. info about the system he uses is at www.diamondkote.com, I am sure you have details in your city who represent this company also.