Firstly, congratulations on putting so many miles on your 4BW. You obviously use it like it's meant to be. Kudos!
I have a '23 5BW (delivered 1/2023) & '23 C8 Stingray HTC 2LT (delivered 9/2022). The C8 has MagnaRide, performance exhaust & GT2 seats. I couldn't get the Z51 package bc it was on constraint at the time I was able to place my order.
While not exactly the same as what you're looking at (bc 4BW vs 5BW), all I can say is, the 2 cars are completely different beasts. To give you an idea on how much time I've spent in each since new, I currently have 38k miles on the 5BW & 41k miles on the C8. I've also had both on the track for multiple track days in each.
Noise: The 5BW is SO much quieter inside than the C8. Now that I've got A/S tires on the 5BW, it's gotten even quieter. This might not seem like a big deal, but on long trips & on a day-to-day basis, being able to hear the radio/Podcast or talking on the (handsfree) phone, this makes a big difference.
Build Quality: The Corvette has classically been criticized for poor build quality & low quality pieces. In the C8, GM really stepped up their game. I have no complaints at all about the touch surfaces of either the 5BW or the C8 & they are pretty comparable.
Tech: I have the exact same setup in both cars as they both have the OEM PDR & rearview mirror camera. Since the dash is customizable for Z & My Modes, I have the dash setup to look exactly the same in both cars.
Ride: While both cars have (with OEM alignment) pretty noticeable understeer, the C8 understeer is more easily managed. Curb weight also makes a difference in the character of the vehicles. My 5BW is ~500lbs more than the C8 & your 4BW is ~200lbs more than the C8. With how much lower you sit in the C8, that weight difference is very noticeable. Even though I have the HTC, the chassis flex when changing directions is so much less than what I feel in the 5BW. I suspect there is more chassis flex in the 4BW over the C8 as well. Even though both have MagnaRide, the ride in the C8 is definitely more harsh even on the softest setting. I suspect the lighter chassis & the OEM tuning contributes to this greatly. Where I live in NC, the roads are pretty nice compared to where I came from in the NY/Tri-state area. If you have to deal with potholes or many areas of uneven pavement, you will notice this much more in the C8.
The placement of the engine makes a HUGE difference in the character of the 2 vehicles. Push either really hard into a corner or on a sweeping highway on/off ramp & you can feel it. The C8 will want to rotate around your seat & the 5BW wants to have the back end swing out like a pendulum. The mid-engine also contributes greatly to the cabin noise of the C8.
Maintenance: Like you, I do almost all my own work on the vehicles I own. The maintenance schedule & work on the C8 is more demanding than on the 5BW. There's an easy hack to adding the extra 2L of tranny fluid into the C8 if taking it to the track. (Some advocate doing that even if not taking it to the track as added protection to the tranny.) Changing out the tranny fluid filter is relatively easy but there are about 100 bolts (slight exaggeration) to remove to get the underbody floor/tray off to get to the filter. As I understand it, changing out the tranny fluid takes specialized tools. Moreover, unless you painstakingly document everything you do & have a failure, GM still might void the warranty.
I LOVE having an MT on my 5BW. I so wish GM offered the C8 with an MT but they've decide that's not going to happen. This one thing alone makes the vehicles so entirely different.
If you end up getting the C8, I HIGHLY recommend getting the HTC over the coupe for one reason: You don't lose any trunk space when you put down the top like you do when removing the targa top. The targa top goes into the trunk if you take it off & you lose all storage space back there. Of course, there's still the frunk, but that's pretty small. It's only big enough to hold a standard sized carry on luggage.
For me, one vehicle is not a replacement for the other because they are so different. I think a good way of going about this is to list your priorities for what you want in a vehicle & what you plan to do with it. Make a Pros/Cons list for the 4BW & the C8 & then weigh your options.
If you can swing it, keep the 4BW & add the C8 to your stable. Good luck!
