In the last year or so the market for 4:3 projectors has more or less disappeared, very few new models are that format now, even the entry-level systems are 16:9 in the main.
Many people use a blank wall instead of a screen, you can make an effective cheap screen from a blackout blind from IKEA for only a few quid.
Hope you don't see rainbows or if you do they don't bother you, the X1 has a relatively slow colour wheel so you'll be more likely to see them than with later models .. if you do then stick at it, first time I watched my Z200 (my first DLP) I saw them but they weren't too annoying, after a week or so I'd pretty much become oblivious to them.
And yes, throwing a project at a wall isn't covered by the warranty.

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