please correct me if I am wrong.

So s5 t2 intake ports are bigger than s4, front, middle, and back.
I have a t2 engine with the oil filter triangle reinforcement. So its a s5 rear then, so the front must be matched with a s5 also? the center ironcan be whichever one, right?

So I have had s4 t2 intake manifolds, but I found someone selling a s5 t2 for real cheap, and my turbo is off right now, so I'm going to get it. I don't remember my oem s4 t2 gasket blocking any of the airflow in the ports.

I thought I remember somewhere that I will need the UIM gasket though, right?

 

S5 turbo does have larger ports at the manifold than s4, ive never measured the manifolds to see if theres is a difference but you'd assume mazda would have increased runner size in the s5 manifold to match, if you've got a s5 engine id go with the a s5 manifold especially if its cheap!

 

the gasket between upper and lower intake is definitely way different between S4 and S5.

the lower is a different part number, but the actual gaskets are really similar, off the top, i am not sure what the difference is

they both use the o rings, which are the same for both, 8527-13-113 i think

 

So the cheap s5t2 manifold was a misunderstanding. He wanted $80, which isn't bad, but I already have new heat reflective tape on my lim, block off plates, unnecessary vacuum ports welded shut, both new oem gaskets with lim to engine already installed. My tuner that is big on rotaries claimed maybe 10hp gain. That makes sense especially when I saw the fd uim mod making up to 20hp at certain rpm. Good hp, but I'm just trying to get my car running again

 

Oh yeah, so is s4 t2 front iron the same, just pet it out as big as a s5 and it's good, our is there less material casted? Just trying to fight out this engine.
My s4t2 blew and I needed a replacement asap and bought someone's engine they said was s5 t2. All I know for sure is it has s5 rear iron and s4 housings. I transferred my oil pan baffle, oil pressure regulator, front cover over. I'm not sure which rotors I have! It has better response, but I got a lightened flywheel , and the street port looked larger than my previous engine. Higher comp pistons, thinner head gasket, lighter rods, advance cam timing?

 

You would hope that they used s5t2 plates as the runners are definitely different, but if its been ported it shouldn't matter as long as the ports and runners are all matched for size, the s5t2 rotors are slightly higher compression (and from memory lighter?) Than the s4 rotors so that would make it more responsive