Seeing caffine really screws me up, Xpand Xtreme caffine free has my vote as well.
I take dumps after, too. But not these bad one's people describe.
If you want something light on your stomach in that sense, but insane pumps try out iForce Hemavol. Just drink a shit ton of water. They say 24-32oz, but I see I needed more.
Try drinking like 15-20oz right before, then taking the 10 capsules and downing another 30-40oz on an empty stomach. Let it sit at least for 30 minutes before you hit the gym.
Pump was insane.