I pretty much agree with BYAIC on most of that.
The shocks are probably the most open question regarding what you are really looking for out of them. If you just want some drop you can do that a couple different ways and a bunch of different price tags. I think you can just get lowering caps and maybe even different springs for the stock ones, but it's a fixed drop compared to being adjustable. I'd also probably buy a full car set. You don't really want to mix those front and rear and the rake of the car is actually pretty important to how it handles, so changing just one end could mess with that.
Aftermarket oil lines are fair cheap insurance. It's not like the stock ones explode or anything like that, but might as well just put on something that has a better chance of not leaking over time. The power steering line as BYAIC said should probably be in that list as well. That seem to be one of the most common problems on the gen 3. JTVSP also makes those I believe.
I personally love my Borlas, though it comes down to what kind of sound you are looking for. To me the Borlas have a nice deep tone and rumble and sound more like a roar when laying on it. Other systems are more **** sounding to me and I would call more like a scream. They give a little more of that exotic high pitch engine note like you'd get with a Lambo or something where the Borla is a little more on the muscle car side of things.
Mine came with a K&N already installed, but if you aren't going to mod the car any I don't think I'd worry about changing it. The factory did a lot of testing and found no real benefit to the cloth style filters when they designed the engine. If you start needing more airflow due to mods like a different cam or head porting then it might make sense, but I wouldn't expect any performance difference on a stock car with one. To each his own though. I don't think they are a bad product by any means, but the more I've worked in an OEM type setting the more I understand why engineers make the choices they do. However, one thing to keep in mind is the factory filters have been known to be hard to come by, so a K&N could make sense because it might be easier to replace the filter elements down the road.
Luckily I haven't had to deal with this yet, but I've heard it has been hard to find them lately. I've driven a car with the Invos and it didn't seem all that different from my Pilot Supersports, but I also didn't drive it for that long. I can say the Supersports are great tires though and very good all arounders that can be used in pouring rain or the track just the same with really nice performance (at least while they still have some tread depth, lol). Like BYAIC said as well, you might see if there is anything out there in a size either way. Pirelli makes the gen 5 tires which are 355s, and I believe they are still the same rim size, so you might try looking up gen 5 tires as another option. Expensive, but what Viper tires aren't...
Never had a stock radio in mine, so hard to say. They are a goofy size (DIN 1.5), so most people just put in a filler plate and change to a single DIN size radio, in which case your options are basically limitless. The rounded corners of the stock radio make it even harder to find something that fully fits the space. The one trick might be interfacing with the stock amp though. I don't recall if it actually takes speaker level inputs or if the Viper radio is somewhat unique and has line level outputs for each channel. It is wired individually though if I remember correctly, but I think you can buy adapter harnesses that make that job pretty straightforward.
