Some things here for your consideration....
My own experience has been predominantly with Continental high-performance W & Y rated all-season tires - I did have a set of Michelin AS3 19" tires with one set of wheels I used....the 19's look nice, but I wanted more sidewall to ease up the ride comfort a bit, though that was when the suspension setup was still stock. We are rather far apart on usage, as I'm nearing 94K miles vs your garage queen's 8K - a bit envious, but I've seen lots of country in the PPV over the past (nearly) 8 years. I've also chosen to move up in size from 235/50 to 255/45 (18) and 255/40 (19) - sort of a back-track on searching for ride comfort, but I think I've found a good compromise with the 255/45-18, even with the shorter tire sidewall - I'm also running a wider 9" wheel with these tires, but I sense you will be staying with the OE size, which is completely understandable.
I think either tire you have identified would be fine, considering usage. Tire Rack & Discount Tire Direct have similar pricing, price matching, etc. TR may offer one advantage in that they do provide a 2 year "free" road hazard warranty, and DTD does not - but DTD does sell one that's good for the life of the tire, basically. I like DT/DTD as I use their house credit program, which offers 6 months & more free financing if you'd rather use your cash elsewhere on a monthly basis, and they often have some special rebates/promos. The Pirelli tire currently has a $70 rebate through both TR & DTD....whether that matters or not. Free shipping, and depending on the states where they do business, maybe even no tax. So, it's a wash on the choice, IMO - my only comment is that tire spec is V rated for both, but in a non-service vehicle, that's hardly an issue.
As to the ride issue, you should be aware that the early 2011 front struts (which I suspect your car has) were a significant contributor to the harshness you allude to. At 8K, I'm sure you are not interested in changing out the offending parts, but the real fix is to use the 2nd design/revised (for 2012) struts, and, honestly, to substitute the SS sedan springs, which also reduce harshness considerably vs the OEM PPV springs. The 3/4" drop is almost inconsequential, but it may not suit a purist's preferences as a police vehicle....but doing all of this DOES transform the car's comfort and driving enjoyment.
The last thing - discussed here in the past - is tire pressure settings. The door sticker says 39F & 44R, if I recall. The 2011 Owner's Manual includes a statement that offers non-pursuit/full-load pressure settings of 36 PSI for all 4 wheel positions. I think the statement was removed in later year manuals, but I live by that statement in the OM, and have not run "door label" pressures since nearly forever.
The one issue in doing this is that the TPMS ends up being right at the edge of activation at around 34 PSI with the factory settings (for PPV), and in seasonal temp fluctuations, nuisance alarms can be frustrating. i worked with my local dealer tech to lower TPMS alarm setpoint to 30 PSI or lower, just to avoid nuisance alarms. My point of all this is that running a target pressure of 36 PSI also aided significantly in ride comfort, and (at least in my opinion) has not hurt handling, performance, tire wear, etc.
As to new TPMS sensors, yes, this is the time to do it. Rock Auto identifies current correct parts - be sure to get the service kits, which provide a new stem seal (new sensor may come with one), a new ferrule (in case of any aluminum corrosion) and a new stem cap. At 8K you might say "why do I need to do this", but the years your stems/sensors have been together, number of times car may have been washed or in wet conditions, it's just a good practice to use the new parts all together - correct sensor stem is aluminum, and the ferrule.
I don't attempt to re-set sensors myself, but with all of your service equipment, it's not in your DNA to have someone else lay a hand on the car - understand in this day & age....I don't know if it can be done without the RFID device that is used to "tickle" each sensor position when doing a re-learn - either a dealer action or tire shop action, as most reputable shops today all do this routinely.