I'm glad mine didn't come with a trunk spoiler. I don't like it anyhow and I'm planning to install an INGS rear spoiler. There's many aftermarket options and the install isn't all that hard whether you want to drill it in or 3M tape it. Here's the stock one on eBay for $110 painted: http://cgi.ebay.com/ebaymotors/PAINT...Q5fAccessories
Aside from the 2011 F-Sport IS350, every other IS350 model came from the factory without a spoiler. From Lexus you can order the 2011 F-Sport model spoiler (prepainted), the dealer/port-installed accessory spoiler (prepainted), or an aftermarket one (usually unpainted).
2011 GSE20 Lexus IS250 Obsidian "F-Sport 6MT" with LSD
1986 AE86 Corolla GT-S Supercharged with TRD Stuff
1993 TCR10 Previa 5MT Race Van
1991 FJ80 Land Cruiser Station Wagon
Im looking to add a rear spoiler as well. This one looks like the Wald and is about $650 so you are looking close to a grand. Its made by AimGain Its too expensive for me right now, so im looking at alternatives as well.