After calling summit, hedman and hooker in regards to headers for the trick flow 23 degree aluminum heads, I finally emailed Trick Flow and got this response. Hope it helps.
Matt,
All of our heads have angled sparkplugs.
The location / angle of the sparkplugs in our head do not usually interfere
with most headers. However, If you should happen to get into a tight spot,
Accel makes a special short plug (It is 1/4" shorter) to help alleviate
fitment issues.
Hooker # 2452 fits fine...
Thanks,
        Art Kakiou TFS Tech Advisor
        Email: akakiou@trickflow.com
        Tele: 330-630-1555 ext:6324
The hooker headers listed above run for $329.88