Frame Connectors bolt in or weld in?

I have been considering purchasing the bolt in connectors from summit. Seems like everyone has welded them in. Would it be safe to bolt them in? My car is probably lucky to be making 300hp. So it's not a 1/4 monster. Just a comftorable crusier. I don't have a mig welder. Has anyone bolted these in before with success?

Thanks