S197.FASTBACKmustang.com - Details of my 2006 Ford Mustang GT. Ford Racing, FR500, Pro 5.0, MGW, Steeda, Roush, GT500, C/S, JLT, SCT, BamaChips, BBR, Mac, Prochamber, Flowmaster, Nitto, SLP, CHE, J&M, Hawk, Summit Racing, Jegs, American Muscle.

Resources

Below is a set of links to various sites or resources I have used heavily in building up my car. I buy and sell alot of slightly used parts to keep my overall cost of modifying the car down. I haven't found a ton of useful sites that are dedicated to S197 information outside of the forums listed below. You will find a ton of useful information within the forums if you learn how to search the content effectively.

Parts

Craigslist.org - I am assuming that everyone has heard of CraigsList. I check this daily to see if there are parts available locally that I am looking for. I have sold numerous things on here for free, and I have gotten some of the best deals on parts from here. Automotive items are huge here.
eBay.com - Again, I assume everyone who hasn't been functioning for the last 10 years has heard of this. I have been buying and selling here since 1998. This was my 1st resource for everything a few years back, but the increases in sales fees has kept me from selling here for a long time. I am still a buyer every now and then, but it has definitely slowed down for me. I have picked up some deals here though.
BamaChips.com - BamaChips (Doug Studdard) provided me with a first rate tune for my car. I would highly recommend working with him if you need a tune for your car. I did the email 93 Race tune and it performed much better than expected.
BlowByRacing.com (BBR) - I have bought a tune and some parts from these guys. The tune was awesome, and they have good sales from time to time.
Brenspeed.com - I almost bought my tune from these guys. Alot of people rave about them, but I have only talked to them on the phone. They are very helpful and if I ever decide to go with Forced Induction I will definitely consider them.
SummitRacing.com - Summit has a huge inventory of parts and they generally have very competitive prices. I have never had any issues with anything I have ordered from Summit.
LateModelRestoration.com - I have bought from them a couple of times. I live in the same state as them, and have generally received my parts the very next day! Prices seem to be competitive, and keep an eye on their Sale section as they have nice deals in there from time to time.

Information

S197Forum.com - This site has the best technical forums for the S197 in my opinion. There are alot of very knowledgable people on this site and I have found it very useful in helping me make decisions/fix problems on my car. It is also a good place to buy and sell used parts.
ModdedMustangs.com - Another forum site worth looking into. There is a ton of content, as well as knowledgable people on this site.
MustangForums.com - The forums on this site have descent content. It is also a good place to buy and sell used parts.
Corral.net - This site has coverage for forums and a place to buy and sell used parts. It doesn't get as much traffic as the others, but still has descent stuff every now and then.
FordMuscle.com - I have been on here for years researching info for my 66 Mustang. It doesn't have as extensive of a community of S197 members and thus content and forums are not as heavy as I would prefer.

Books

Building 4.6/5.4l Ford Horsepower on the Dyno - This book covers many modifications to the 4.6 Liter engine and shows before and after dyno results for those mods. It covers a range of topics including: intakes, cams, exhaust, nitrous, superchargers, turbos, etc. There are some 3-valve tests in almost every section, but not as much as I would have preferred. I did like this book because it provided some real numbers and dyno graphs to see exactly what might be expected for various mods. To me this is much more useful than someone telling me that their shorty headers only netted 2hp on the dyno (when if you look at the dyno graph it built considerably more power and torque below the power curve). This is probably the most useful book I have found for my 06 (partially because there isn't much to choose from).
How To Build Max-Performance 4.6-Liter Ford Engines - This book is good, but not great. It is pretty cheap so it is probably worth the cost unless you already have experience with the 4.6 Liter engine. I haven't read it from cover to cover, but have generally read specific topics of interest. It has sections for every major component of the engine. This is part of the weakness of the book, because it maybe covers too much without enough details about anything specifically. It is really good for a newcomer to learn the basics of all of the components of the engine. There is not a ton of direct 3-valve information in here, but pretty much everything covered applies.
How to Build Supercharged & Turbocharged Small-Block Fords - This is a book I have had for a while when investigating supercharging my 66 Mustang. It provides a good overview about adding a supercharger or turbo for various small block Ford applications. It covers all the main options for forced incuction and also provides details about a few specific kit installations. It doesn't have direct information about the 3-valve motor, because it was published about the same time as the S197 was first mass produced. It is definitely a good starting place if you are wanting to learn more before jumping into adding a kit to your car.
Automotive Electrical Handbook - This is another one that I have had for a few years that I used alot when rewiring my 66 Mustang. If you are not experienced with wiring (like I was) this is probably a good place to start to allow you to feel more comfortable before attempting a mod that involves wiring.