The only difference is the connection on the caliper but they still both bolt off the same way. The install is very straight forward. Remove old and replace with the new. Use a proper flare wrench to take them off to avoid stripping the nut.

As to which ones to purchase, either will be fine. We're talking about a couple bucks after all. If I were you I would connect with the vendor that I mentioned earlier or another evo specific shop. It appears the the difference is only in regards with the IX's so you should be able to get that squared away instead of wondering if Rockauto's database is up to par.

 

Found the centercaps for the evo8 stock enkeis
They are part number "MB816391"
I think these enkeis are called TS6 but not sure

 

UPDATE
Thanks to everyone who participated in this thread.
I'm gonna make a parts list for the brakes later and post it for future ref.
Brakes are done, trans is broke in and tune is great.
...but I didn't get tires in time for event one at my autox so I had to ride with a buddy. -_-

My painter was going to have everything done on time, but when he got the 4th wheel stripped he noticed a pretty big crack, so I've ordered a new wheel, and he's going to paint it to use as a main while the cracked one will be repaired and used as spare.

KevinD at Evolution Dynamics really knows what he's doing.
Car makes great power and gets pretty killer mileage as well, without too much drama.

Chad Hayes is another genius I need to thank. The rebuilt transmission is butter smooth, and has yet to refuse to do anything I've asked of it. The 4.11 fd is probably another contribution to the extra mpgs.

These new brakes are hilariously good. I've begun slowing towards a corner and wound up having to accelerate again before I get there, because I didn't expect to slow down so much. Huge difference.

As far as tires go, I found a local shop that seems like they can hook me up with what I need at a decent price.
Prolly gonna go with ZII since that's what everyone is suggesting, but I found the bridgestone Potenza RE-11A
http://www.tirerack.com/tires/tires....omCompare1=yes
and noticed that no one mentioned it despite it having 200 treadwear and a pretty decent looking cap.

 

The RE-11's cost a lot more and I think they work better for like lighter cars. The ZII is an amazing tire and will last longer then any other tire in its class on an EVO, except for maybe the rivals.

I got like 15,000 miles and a full season of autox on my z1's running -2degrees up front and zero toe all around.

I'm glad you like your brakes. I tried Hawk HP+ pads and they were the worst noise I had ever heard from a set of brakes. Like the squeal could wake the dead.

 

Yeh these only tend to squeal when I get them pretty damn hot but I probably didn't put enough of the grease on there. I had a blast breaking the pads in. Felt like my face was going to come off during the hard stops. Then when I got to the gas station to let them cool, there was smoke billowing out of each wheel well, and everyone kept giving me strange looks.

 

Parts list:

Brake Rotors:
Centric Stop Tech
Fronts
126.46064SL
126.46064SR
Rear
126.46065SL
126.46065SR

SS Lines:
Centric Stop Tech
Front
950.46005
Rear
950.46504

Pads:
Hawk HPS
Front
HB453F.585
Rear
HBF180F.560

Probably the hardest part was cleaning the calipers. Brake dust was caked on. Looks like the prev owner rarely cleaned them, so I had to scrub, use compressed air, and about 5 cans of brake cleaner. Once that was done, everything else was pretty straight forward. Pull the clips off the old lines. Remove the lines with the proper wrenches. Clean, and refit everything to the proper torque. Had to replace a bolt on front left b/c prev owner left off a washer and the bolt went down far enough to eat the end off with the rotor which caused the bolt to flare out a bit and almost messed up the threads on the caliper. I just put a new bolt with a lock washer on it. Got a surprising amount of air out of the lines, but I think part of it was me not letting the new lines fill with fluid before bleeding.