Highlights of what you could buy in 2006:
1) 3rd gen LS430
The 4.3L 3UZ is showing its age at this point, but the performance is still very relevant today. In fact, it's very close to what you would get from a 2026 LS500 (not much better acceleration, similar fuel efficiency).

Even before the very high-tech 4LS, the LS430 still had some state of the art options at the time: dynamic radar cruise control, pre-collision system, soft close doors, adaptive variable air suspension. The rear executive seating includes a cool box (not available on the 5LS).

2) 3rd gen GS/GS Hybrid
The 3GS launched with the 3UZ at first with 1UR arriving later in its cycle. But even with "only" 300hp, it was one of the quickest mid-size sedan of the time. Lexus actually had to under-rate its performance so it won't step on the toes of the flagship GS450h. The GS430 is actually the most reliable one to get in this model year.

The standard 6-cylinder option was the D-4 3GR-FSE since the D-4S equipped 2GR-FSE was not ready in 2005. This was one of the worst variants of the GR V6 family due to the direct injection-only D-4 system. Many would skip the 3rd gen GS300 and go for later MY GS350.

In 2006 the GS450h was available, and it was by far the most advanced Lexus product at the time. It uses a 2-stage E-CVT to achieve better acceleration and highway fuel economy. If you buy one used the battery pack will likely be a problem, but unfortunately this was also when most Toyota hybrid batteries are easy to service. There are many repair shops (thanks to the popularity of the Prius at the time) that do battery reconditioning, individual cell swaps, or straight Li-ion conversions, all at much lower cost than replacing a full pack at a dealership. I would consider this a good project car to test how good these early THS can get with modern Li-ion batteries.

The 3GS was absolutely packed with standard features and available options. It's the first Lexus model with VDIM, which is a very advanced chassis management system including some very high-end tech: adaptive variable suspension, variable gear-ratio steering, active stabilizer bar, and electronically controlled braking. But on the negative side, the 3GS became very expensive, with the V8 model and hybrid model almost matching the LS430 flagship in price. I think this is a reason why the GS gradually fell out of favor to ES.
