At this point you are not likely to get a big discount because 19s are coming soon. Further, the demo mileage is negligeable so don’t expect a bigger discount vs a new unit but try to shoot for at least 10-12% as a base. What model type is this, a coupe?
It’s only cheaper if you would get it serviced at the dealership. The most cost effective way to service your vehicle is with an independent mechanic that you trust. Performing the scheduled maintenance is required, it is not required have service at a Lexus Dealership.
For example, on my 30K mile lease for the Lexus RC-F, the 1K and 5K service were included regardless. Additional services were as follows;
10K Service - $75 - Includes 5W30 oil change/filters and cabin air filter replacement ($10)
15K Service - $65 - Includes 5W30 oil change/filters
20K Service - $75 - Includes 5W30 oil change/filters and cabin air filter replacement ($10)
25K Service - $65 - Includes 5W30 oil change/filters
Total 3 year cost of $280 and I don’t have to drive/deal with the dealership. Even if you residualize you’re coming out way ahead just going the independent route.
If you read the Scheduled Maintenance log for your vehicle, it’s a lot of “visual inspections”, “checking fluid levels”, “checking window wipers”, “checking tire thread”, “check installation of floor mats”, etc.