It's so weird when people have commented on the 5-spd feeling "rubbery" because for me the 6-spd felt super rubbery and my Shep 5-spd is very mechanical and crisp. Now, I've never driven an OEM 5-spd, so maybe the stock 5-spd feels even worse than the 6-spd did. Also 4cdndctn, I understand the motor can change the driving dynamic, but the OP was talking about a CT9A not a X and the dynamic is less important than A) Will the 6 spd blow up under the conditions the OP needs it to perform in and B) assuming it will hold up, is the gearing actually preferable.

My experience driving a IX with both transmissions on the track is that the the 6-spd will not hold up consistently (your mileage may vary) and in my opinion the gearing is not preferable. It is different, which depending on the individual track, power of the motor, and aero can change shift points dramatically. That being said, would I swap out a perfectly good 6-spd for a 5-spd? Probably not... I ran my 6-spd until it stopped working. But when I came to the choice of rebuilding the OEM 6-spd, getting a built 6-spd, or swapping in the built 5-spd I thought the choice was obvious. The built 6-spds are an improvement, but cost as much as a built 5-spd and have very little testing, and don't address the issue of insufficient fluid. In fact, in my case the failure in my transmission would not have been prevented with a built 6-spd. It wasn't a gear teeth failure, it was the collar between 3rd and 4th. I personally don't think there is a benefit to the 6-spd and there are noticeable disadvantages.

 

38,700mi in 7 years of abusive and I finally lost 4th and 5th gears. No cooler, just regular oil changes. ~430/410 for power and relatively smooth driving.

She grenaded on turn 5 in exit on full throttle at around 6k, which quickly became 8.5k. Not quite the experience I wanted my student to have, but he enjoyed himself regardless, for the prior 5 or so hot laps at least.

I have nothing but great things to say about my experience with the 6spd. I have a 5spd going in since sourcing a built 6spd is a challenge now and timing is an issue as I have a busy track schedule this year. I could put in a used 6spd but decided not to.

With 2 events in the next 4 weeks where I'll be able to determine which one feels better and is better suited for the tracks I drive, the way I drive, I'll reply with feedback. Time to slap on some Hoosier 80s now too

 

Yeah, sorry to hear about the 6 spd going up. I definitely wish you luck with the 5 spd. I'm feeling some grinding with 5th gear synchros at high rpms on my 5-spd now, but I think I will be ignoring it for the rest of this season unless it gets worse. When I do decide to crack the trans open again, I think I'm going with some custom gears as I'm pretty annoyed with the retarded jump from 4th to 5th gear.

Both Evo transmissions have issues in my mind. I definitely prefer the 5-spd, but the need for the OEM gears to have the short "rally" gears and then a tall highway gear makes the jump to top gear just too high. I'm never below 3rd gear on any track, and many times I'm at rev limit in 4th wishing I could go for 5th, but not carrying enough speed to be in boost.

 

It's all good, we shared many good times, and quite a few FTD's
What's your rev limit and what are you using for a turbo?

 

I'm using a ported CBRD BBK-Full with Kelford 272 cams with a 7600 rpm limit. I generally shift earlier as I'm not making a ton of power up there and I'm on stock springs/retainers. There are a few corners I need the rpms though.

 

i think blackened was just making a point with regards to the 9s having mivec, no? (and the 8 and 9 have different ratios)

 

Yup.