Good questions.
The cutoff is when the drawing takes place see the first post. You need to be in before that. Please don't wait until the last hour though, I may not be able to include you if I don't see it in time.
The shipping charges will be included in the project total. If the account value has money left over I will draw from that to ship the headers... if not, shipping is on me.
Yes they will fit your 98 Regal.
The video will be on my youtube channel for all to see.