I ran the nickle/chrome tti's and now Dougs.
The cppa/tti's turned a dark color and then sarted rusting where two tubes come close to each other.
The Dougs were beautifull at the beginning but turned dull quickly and within 5-6months later I started seeing rust specs here and there. Last march when I pulled my motor the Dougs were covered with rust specs(they were on the truck for about 9 months).
Cppa/tti's were used on a daily driver in ALL weather. The Dougs were never driven in the rain but the truck was parked outside 24/7.