Turbosmart Wastegate Screws

need some help. I'm trying to find replacement screws/bolts for the inlet flange on a Turbosmart Wastegate. Was just told from Turbosmart support to go check my local hardware store, I'm a little hesitant to do that. Any suggestions where I can find the right screws for this thing. This wastegate came with the RevHard kit back in 04-05, 38mm with a 7lb spring. I have had these bolts back out on my 2-3 times a year, any thoughts on how to remedy that as well? I've tried locktite with no success.

Size : M8x35. Might be M8x25

Thanks guys!

the 2 bolt flange? m8x25 sounds about right. nothing wrong with hardware store bolts, I use zinc plated hardware on all my stuff if they have it. it's usually pretty high grade stuff and the zinc plating will keep it from corroding. it's the same stuff your spark plugs are coated in.