Refi Questions - Cash out for investing?

[Emory Peterson]

Howdy there everyone!  I'm starting to look into investing in a few small properties OOS.  That said, just by chance I'm starting the refinance process on my primary residence.  It's worth ~$350k and I owe $127k, I'm only refinancing to drop from 3.5% on a 30 year to 2.5% on a 15 year.  The original loan was for $176k, 4 years ago.  I've paid quite a bit extra, the payment will remain almost the same with the rate drop and lower principle.

I've got 50-100k in cash I'm willing to use for upcoming investment properties, so I don't particularly "need" cash from the refi.  But I got to thinking, if I were to pull out some equity at the 2.5% 15 year rate, or even do a 30 year at 2.875% (these are the numbers my lender is quoting me) would I be smart to do so?  It's a crazy low rate to borrow money at in my eyes, but I'm also not a huge fan of getting my primary residence too tied into the investing side if that makes sense?  Our very inexpensive mortgage feels great and offers a real sense of security.  But I don't want to get out there and struggle to buy because I'm a bit short on cash, or need to finance and lose the deal etc.

Thoughts?