So I'm finally installing my bbi catted exhaust, champion ic's and evom headers. They should compliment the ipd plenum, y pipe and bec filter. I'm thinking about moving up to a stage 3 ots tune and install some new plugs and coils while everything is a part. I have a few questions. Like what is considered the best plug for more boost? While turning up the boost I went with one step colder and lowered the gap with my other cars. What is the plug of choice here?

I'm assuming the stock coil packs are fine? I was thinking about changing the serpentine belt as well? I will also need a 3 bar map sensor. How are the oem diverter valves? Is this something else I need to upgrade? Your thoughts are greatly appreciated!

My car is a 2011 TTS with 20K miles. The previous maintenance was not recorded very well... I'm trying to be proactive. I've read about several others that started to mod their cars, only to take a step back to deal with maintenance issues brought on by higher boost...

 

From what I have read you are heading the right direction. I am doing the same, changing plugs, coils, diverter valves to Forged,. However I am keeping the same stock plugs heat range but gaping them very closely to the specified gap by tuner.

 

Glad to see you're enjoying the car in good health!
Sounds like you're on the proper mod path to make this thing an *** kicker.

 

This right here, same thing applies for 997.1s. I am using stock plugs but gapped to a specific gap. The list you have on parts to refresh/upgrade is on point. The rest is making sure you do a boost leak test after you installed everything. Double check things up top also, vacuum lines etc.