what kind of issues will i be running into when i switch from my t-5 to a th350? as far as wiring and mechanical issues, will i have to swap the crossmember? or get a different driveshaft? any input would be great, thanks

crossmember and driveshaft are fine, but unless you've gone aftermarket you won't have a torque arm mount without buying/building a bracket for it.
- I have heard of some poeple claiming to have to modify the crossmember, but it shouldn't be different....

As I asked in a post I made this morning, what length tailshaft is needed to keep the existing driveshaft?

you need the 9 inch tail stock if you go with a TH350 in order to keep the existing driveshaft.

i dont have a welder or anything and id rather just bolt it in, so where can i buy a torque arm mount bracket?

also i noticed on my th350 theres a connector spot looks like a 4 pin connector, what is that?