Keith,
There are a lot of other people on here who are a lot more knowledgable on what to look for, but I'll give it a quick shot here.
First off, it's impossible to have a 2003 VX. They where imported into the US from 1999 to 2001. The only differences between the years is that the 1999 models have 16" rims and manual climate controls. The 2000/2001 models came with 18" rims and an "auto" mode on the climate control.
That being said the main thing to check is the oil level. Our engines tend to burn oil straight from the factory and you really need to stay on top of it. A few people here have blown their motors due to lack of oil. I check my oil EVERY time I get fuel, and many of us here will replace our PCV valves every, or every other, oil change.
I think I read that the VX you're looking at already has the window sticking problem. That's a pretty typical problem with all VX, and a member of the site has come up with a really great fix (I plan on buying it soon) that replaces the plastic window mount in the door with a metal one.
You can check to see if the shocks are in good shape, but those are easily replaced with some after market shocks. The original VX shocks are made by KYB and have a resivoir built onto them. They are expensive to replace with original ones, and can cost a few hundred dollars to rebuild so some members have replaced them with Rancho's.
I'm sure there are other things to check and hopefully some other members will chime in, or you'll find the information you are looking for using the search function. I haven't really had any issues with my VX (knock on wood) and I absolutely love it.
Welcome to the obsession.
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