Since the introduction of the Lexus IS350 in 2006 it's been a great competitor to BMW's 335i. But aftermarket support for the IS350 has been fairly weak and even worse for the IS250. But some good news for IS350 owners. AZ JB of ClubLexus.com has had his car at PPE to develop new headers. The fruits of his volunteering have finally ripened. On the dyno they were able to achieve 265rwhp before the headers and 286rwhp afterwards. This is with his custom exhaust, but the only difference between the two dyno runs was the addition of the new PPE headers.
The difference between the dyno runs was 21rwhp, but they say expect something more around 16rwhp. The quality of the headers look pretty nice. As seen here the quality is up to part at least from a visual perspective.
And here is video of them on the dyno. Sounds pretty decent, but probably could sound better with different mufflers.