Selling Vacant lot

[Nikki Saya]

Hi,

I've listed my vacant lot for sale, I've got interested "potential" buyers.  They are requesting for engineering plans, structural & plumbing, soil, bio reports & property survey.. should I give them all these reports without an offer?  I've spent a lot of time and money on these soft cost/ reports and do not want to just give them away?  I'm afraid to just hand it off... Does anyone know if this is pretty standard of potential buyers to ask for such items when it comes to vacant lot? Would appreciate any thoughts/ feed backs on how to reply to these potential buyers.  Thank you very much for the help!