Hey guys, I am looking to order some of the Trick Flow TW 11R's and I see that for an extra $100 you can get the option of Titanium Retainers. I did a search where I found people talking about them, but nothing stating when you should be running them. I'm just trying to figure out if it's worth spending the extra $100 for them. Are they for only high rev applications or is it more to do with strengthening the valvetrain? Are they worth it on a street application or strictly drag? Just some info on the subject would be great guys. Thanks, Garrick A.R.