Whats the difference between the Lexus is 250 and the is 350? Also, whats the difference with the is-f?

I believe the main difference between the IS250 and the IS350 is engine size. The IS250 comes with a 2.5 liter V-6 with 204HP and gets between 18-29 mpg depending on transmission and drive type. Along with the standard rear wheel drive, the IS 250 also offers an AWD model, which the 350 does not offer. The IS 350 comes with a 3.5 liter V-6 engine that has 306 Horsepower, and gets 18mpg city/25mpg highway. I am not sure if there are any other main differences between the two. The Lexus IS-F is the performance sedan model for the IS line. It comes in only 1 trim, and features a 5.0 Liter V-8 motor that has 416 Horsepower. Even with all that extra power, it only gets slightly less fuel economy than the other IS models, (16 city/ 23 highway). It is also much more expensive, starting out around $55,000 I believe. That is nearly $10,000 more than the most expensive IS350. All of these models are based on the same vehicle. They are very reliable, and have a great mix or luxury, comfort and performance. Hope this info helps.

250 and 350 is the engine size (2.5 L and 3.5L) the 250 is RWD with AWD optional and the 350 is RWD only. The 350 gets a bit less to gallon, but more performance and tends to last some miles (ive heard 1000-100000 miles) more. the IS-F is a performance version of the IS 250 and IS 350. The basic styling is same, but the body is slightly different (sporty look-bumpers, fins, etc) and the interior is VERY different- more a sports car feel. Lexus calls their new line of high performance luxury cars the "F series" and is usually called F-Performance. The whole IS line is very nice, but if you live where it snows, i would go with the IS 250 AWD. If your looking for a car a bit more than your regular camry and Accord, go with IS 250 RWD. If you want to go fast and have a feel of a sports car, go with the IS-F. with the IS series, you can't go wrong