I grew up in L. Highlands and know the area well.
In general the "newest" homes are of 1980's vintage, although there has been some tear downs of older homes and new construction.
White Rock Elementary is considered the best, Skyview generally the worst.
"L" Streets is super hot.
While the largest newest homes are near Forest Meadows Jr High- and Skyview- the closer you get to Forest Ln the dicier the area.
Although N of LBJ is still in L Highland HS district, I'd stay away from there. The homes are bigger and newer, but the values have not held.
Hope that helps, call me if you'd like to see the area in more detail.