Turbo is going to be quite a jump in skill level and understanding, so don't worry about that too much right now. In fairness, not much that you do for NA mods translates over to what you'd use with a turbo.
You're not going to hit 200whp, but 200hp at the crank is doable with header, 2.5" exhaust, RRE's underdrive pulley, a cold air intake, and a tune. Lightweight wheels will also help. You should be able to hit about 190whp/210 crank on a healthy bolt on/tuned GS manual, or around 180whp/210 crank on the auto (again, if it's healthy).
However, there are a couple things to keep in mind. A 2.25" exhaust is going to give you a nicer driving quality than the 2.5", as it'll make power across the rev range better. It won't give the same peak horsepower, but will feel faster in most use. As for that pulley, the downside to it is that you lose the damping ability of the stock crank pulley. That adds to crankshaft vibration, and wears the rod and main bearings quicker. It's not like you'll fry a set of bearings in 50,000 miles with it, but your chances of seeing 300k miles on the engine drop quite a bit with one.
Basic easy and streetable, the RRE header, a custom 2.25" exhaust from a local exhaust shop made from MILD STEEL not stainless will sound best at a minimal weight penalty, use a turbo muffler (high flow, but has baffle plates inside still so it isn't straight through), run a resonator if there are no cats, Fastworks tune (expect this to take months, there's a huge demand and literally only 1 tuner), DC Sports cold air intake (easy first mod, makes a neat sound), a hydro shield for that cold air intake (reduces the chances of a wet filter ruining your fun), and you could call things there engine wise.
Suspension wise, ignore the cheap eBay no name brand coilovers, ignore the MaxSpeedingRods, they have a bad track record for seizing up or blowing valves. The cheapest brand I'd say worth considering at all is KSport. They used to be problematic, but they've stepped up their game. If you are gonna go cheaper than that, get good lowering springs. The cheap $100 ones will ruin the drive quality of the car, handling ability, and just aren't safe.
Weight reduction can be as mild or wild as you want. I've got a 2670lb GT, and that involved a lot of cutting and lightweight parts. A lot of people will take out their spare tire and tools as the first weight reduction and get a CAA/AAA membership. That's all fine and good if you're willing to let a flat tire take up 4 hours of your day waiting on a truck, getting towed home, and then swapping to a spare. But it's probably best saved for being put aside at the track. Some weight reducing options that won't hurt day to day life include: Carbon fiber hood/hatch, aftermarket head unit, remove the back seats (if they're unused), lighter battery (but not smaller or lower CCA), cold air intake, coilovers, lightweight wheels, trunk cargo cover. Then you could remove plastic trim panels inside, however some cover sharp edges, and they all quiet down the ride. Could even go as far as to then remove the carpet, headliner, sun visors, dashboard panel, etc. It keeps going and going. Lightweight bucket seats and an aftermarket steering wheel are a poor choice as they remove the airbags from each.
