Posting this for a friend. It's an Autopower bolt-in 6pt for a 240sx, used for auto-x and track days. Should he reinforce the mounting plates some more, or are the provided "sandwich" plates sufficient? They look a little small too me. Thanks for the help and sorry for the pic size.

 

They are appropriate to the rest of the structure. For what you describe, it's fine.

Have fun! I remember how many 3/8" bits we used putting ours in years ago. It was enough to convince me that paying someone to weld one up was worth every penny.

K