So I had a few offers for a Spawn $325 shipped and one for an Angel E from Australia $360 shipped. These were all completely reasonable offers and I thank those that made them. In researching The Angle E mod I found that it was designed to be like the Engl E 530 preamp. So I started reading up on it and listening to demos. It's a two channel tube preamp with two gain modes each. It also has some other unique features. I found one used in mint condition for $385 so I jumped on it.
Even if I love this preamp and decide to keep it, that 4th empty slot in my RM4 its still going to need filling! I'll just have to save up a bit for the next mod. I just want to thank everyone that reached out. I'll likely be in touch again in a month or two!