I've owned my TR for well over 30 years, and my father had one for about 6 years before that. My grandfather ran a Triumph dealership. So we come from a time when they were new. However, my grandfather also ran a race team out of that dealership, and so those cars got modified.
When I first built mine, I stayed pretty doggone stock. It was not long however before I started modifying it. My modifications were pretty particular - I wanted modifcations that looked like they belonged on the car from when it was relatively new but added something to the car. I've stayed true to that over time.
I built a new engine for it 2 summers ago. While I built the engine up significantly HP wise, it really looks pretty stock from the outside. Only the triple sidedrafts hanging off the side are the real hints that more is going on inside. But even there, I went with original DCOE 40-18's, the orignal Italian made DCOE's that were spec'ed for the car back in the '70's, and I put them on a Cannon manifold as well that matched the carbs.
If you look hard under the hood, you'll see the harness for the wide-band O2 that is in the header, but the gauge on top of the dash is color matched to the old Smiths gauges, so it is not too terribly out of place though the reading is digital.
Recently, I added a limited slip differential from an Infiniti under the car along with CV joint axles and hubs. The performance upgrade from the diff, plus the fact that it does not leak, along with the fact that I've finally addressed the glaring weak point of the fragile rear hubs is a good thing. I'd dare anyone but another Triumph owner to pick out the difference. You definitely cannot tell without crawling under the car with a flashlight.
A non-stock electric fuel pump under the gas tank feeds the Webers, but is concealed under the rear fender. An impact switch from a late model Ford is up under the driver's side interior paneling where I can reach it but cannot be seen. Safety. Only visual giveaway is the blanking plate on the motor and slightly odd fuel line routing under the hood.
Nothing I've done to the car is pointless - it all adds to the comfort, safety and performance of the car. Everything I've done is as clean as possible and concealed. All of it is reversible, though I have no intention of doing so.