Ya, iGO is definetly a memory hog. Add in TTS voices and you need quite a bit of free RAM. Are you using TTS voices? If so, trying it without can make a big difference.
Not sure about you're router issue. Looks like you've got some research to do
For MMS, what carrier are you with? Sprint isn't currently supporting MMS on our devices, so you would have to use one of the workaround programs.
sMMS is probably the best, most complete solution out there for Sprint users.