[HTC Sensation] trkaaa:
Good choice ARHD 6.6.3 , it is the rom i recommend for first installation for ICS and also for daily use ( the firmware and the Rom are by same developer which adds more compatibility )

this rom requires to flashed firmware 3.32 ( which includes the Radio 11.22.3504.07_M ) , the first Part of the Radio name " 11.69.3504.00U " is i guess is related to carriers or rom not sure ( P or U ) !!!!! , but they are sameRadio

Radio choice is location specific , the best for me could be the worst for you , i live abroad and i use the standard Radio that came with the firmware ( i have Sensation 4G ) , so later on after installing the rom you can try to install the Recommended Radio and see for your self the difference in signal and data speed , but it not obligatory to flash it

i feel that you are still confused about firmware , i 'll try to explain it :

when htc releases a new official RUU ( its version for example RUU 3.32.401.105 ) , the developers modify and optimize that RUU and it is Called Custom Rom , for each custom Rom in the OP the developer states the version of the RUU he based his custom Rom upon and the firmware version which should be flashed with his rom

the first two fields of the RUU name determine the firmware Base ( i.e 3.32 )

for ICS , you have to flash both a custom rom and a Firmware ( same base of the custom Rom for example 3.32 )

if you are on GB and want to go to ICS then you need to upgrade your firmware and install the matching ICS Rom for the firmware

if you are on ICS and want to revert Back to GB you will downgrade using firmware 1.17 and install GB Rom

ICS Firmware are 3.12 , 3.24 , 3.30 , 3.32 - GB Firmware is 1.17

the worst firmware in my opinion is 3.12 ( it can be used for GB not recommended by me , dangerous waters ) because it has locked hboot 1.23 , you should not use it unless you have to and for min time and get away from it , that is the reason i advised you to stay on GB for a while until you read enough , but now with all these Posts i think you can start but carefully and always ask first

i feel that you are confused a little regarding Radio and S-OFF from what you've read else where ,

if you are S-OFF Permanent or Eng ( Eng is not applicable for our device ) , then you can flash radio no problem

But if for example you flashed an RUU and it replaced your hboot with the original locked one , then this original hboot will not allow you to flash radio although you are S-OFF because locked hboot don't support the command " fastboot flash .... " , if you replace that hboot by using the correct firmware the unlocked hboot will replace the original hboot and you can flash ....

your current configurations are good to go

to find links , steps , methods and Guides and if you feel confused you can follow my easy method for installing ICS which i did it myself for installing ICS , go here to Post 2 , follow the second title " 2) Easy Method for Installing ICS Custom Roms ( S-OFF Devices ) "

if you want to do S-ON to return it to warranty , then install GB RUU then S-ON , noting the following :

the RUU should be the original RUU or very similar ( not any one you choose by yourself )

you should be super cid before that

follow step 5 in this Guide for S-ON Guide to S-Off, Unlocking, Root, etc

Never S-ON on ICS software , because you will not be able to S-OFF again using Revolutionary after that ( Revolutionary don't support hboot 1.27 )

if you want to S-ON because you like official Software and want to receive updatea then you don't have to do that , you can still be able to install official Software and receive updates while you are S-OFF by two methods :

while you are S-OFF , install GB RUU , go here for method [GUIDE] Using the ICS OTA files will receive updates ( but you loose custom recovery , hboot is replaced by original locked hboot , loose SU and you need to install it again )

or better than that install ICS Rooted OTA ( maybe will receive updates ) here Latest Stock ICS Rom , each issued OTA the developers immediately root it with no modifications at all ( but you keep custom recovery , keep unlocked hboot , keep SU ) , note you have to install the firmware before the Rooted OTA , after that flash Rooting tools , and for each OTA comes install the new Rooted OTA

So , Bottom line , Don't S-ON while you are on ICS RUU