OK i'm r eally sorry and i do know tht this has been covered and wish i could search but it just isn't workin for me right now so i'm posting a thread. It seems most people on here agree that the s5 n/a manifold make more power than the s4 na manifold. my question is what should us us upper and lower or just upper? and is ther e a write up on anything that migh be tricky? i plan on doing this along with a header, undrivepully, and remove my emmisions, this all should put me near a mid 14s 1/4 mile!!

 

bump

 

I have done this mod to my car. it does help out alot and is not too tough. Take your time and it will be much easier. I used the s5 upper and the s4 lower, the only problem i had with this was the engine bay side stud on the s4 lower does not line up with the s5 upper. I solved this by removing the stud and "U"ing that spot so i could slid a bolt and nut in there. The bolt did end up vibrating loose and comming out but this could have been solved with a lock wassher. Other problems i encountered were having to remove the EGR vavle and making a block off plate, and on the rear Iron you have to grind off a bit of metal on a nub that sticks up ( i wish i had a pic ) so that the upper will seat with the lower if you don't it will hit and raise the back of the mani. one other thing is if you are going to use the s4 TB you need to cut/grind the nub off from the bottom so it will go onto the s5 upper.
i hope that helped a little, if you have anymore questions just ask. once you do this you will be running the exact same setup that i ahve. I have the s5 upper, rb header, unorthedox racing pully, electric fan, cold air set up. It's a good setup, it went well but right now Rotary Resurrection is rebuilding my engine with a large streetport, and s5 rotors so it should be good. I had my car dyno'd on the day it blew and it was at 134.8hp and 128lbs of torque. For a weak motor that died that day i think that's decent. Also it was heat soaked bad! ok i hope i helped.
Dom

 

i have an S5 and have NOT done this, but from reading posts it seems the consensus is that the best way is to use the S4 LIM and S5 UIM and up as Dom stated he did.