said by t_waly7:If I want to add a second modem to double my lowest speed do I need a second line (dry or wet)?
Yes.
Do I need to tell TSI so they can increase my bandwidth?
No. Order a second line with or without phone service.
Can I just add a second line myself and get better speeds?
If I split the wires myself, who do I get to activate the second line?
Not sure what you're asking. Call TSI and ask for a second connection and arrange a modem for yourself, much as you did for the first line.