and is the range difference that significant.
Depends on what you consider "significant" in relationship to the range, and what you are going to use it for.
Since you are an experienced tesla owner, you know that you will only use from 90% to about 20% of range for daily driving. A SR+ is rated at 263 miles. 90 of that is 236. 20% of that is 52. 236-52 = 184 effective range, and thats if miles roll off at 1:1 which, as a veteran tesla owner you know they dont.
The effective range of a SR+ Model 3 is somewhere between 150-184 miles, when new and there is no degradation. Whether this matters to you or not depends on what you use the vehicle for. If its for commuting back and forth to work and work is <100 miles round trip, and you have home charging, then this is a complete non issue.
If its for commuting to work, and work is 150 miles round trip, then there is an issue, especially in the winter (for example).
Same calculations for a LR Model 3 are (currently), rated at 353, 90% is 317, 20% is 70, 317 - 70 = 247. Since miles dont roll off 1:1, the effective range of a LR model 3 is going to be something like 205-247, or an effective difference of roughly 50-70 miles or so. Might be significant, might not, depending on your circumstances and use case.
The other differences are, the LR AWD is much faster off the line (much), many people find the premium audio in the model 3 nice (and some dont care or dont see much difference between the two, audio is very subjective), and because the battery is bigger in the LR AWD, as the battery degrades, you still have longer range left than the SR+.
Whether that matters to you or not is a personal thing.