Elijah Leviticus Farrell

Hello all, I've recently purchased the above mentioned car. It's high miles, and I'm looking to do some preventative maintenance. First of all though, I'd like to do some research to know what I'm getting myself into. First of all, who makes this Turbo, and what model is it? The farthest I've gotten is that I believe it's a Borg-Werner Turbo, but that's all I know. Secondly, what are it's dimensions, and what does that mean to me? Lastly, I've heard that a stiffer waste gate spring, along with a tune and new hoses all around can greatly increase HP while keeping reliability fairly normal. Is it an internal Waste Gate, or external? Thank you, and I'm sure with more answers, I'll have more questions. If you want to put your 2 cents in, it's got roughly 175k miles, should I just replace/upgrade my turbo while I'm there? If so, what are your recommendations? Would I need a new intercooler? How about exhaust manifold?