I'm looking at Crazy Carls 2/3 compound kit for S300 w/475 right now.  It sounds like I have the right smaller turbo for this to work, just not sure which larger turbo I should go with.  My current turbo is the GXE 57/65/12 gated T3, for the new S475 it lists either a 96/1.32 or a 96/1.15.  I'm not sure which one would work for me.  The truck is just an occasional driver/tow rig so I don't need max power.  I would like to keep the boost around 50psi as well.  I have head studs but am still rocking the OEM head gasket with 250k miles.  I sent an email to Carls asking their opinion as well, and to see if maybe there were other options.  

If your build plans change, I’ve got a practically brand new (100 miles) 62/68/12 SXE I’d trade you for your GXE. 

Smaller housings are better for spool, larger for power. 

 

You could also check out power driven diesel's ultimate towing twins. Its a k27 and an s369 if memory serves.. its meant for 5-600hp and fast spool.

 

Wonder if you can call them and ask to keep the gxe instead of swapping everything..

 

 

Some turbo sizes for comparison. Ignore the prices, also list is reference only and may not be perfectly accurate.

I looked at a few, CC, PDD, and Pusher.  I would like the PDD kit if I was replacing both turbos, but I would prefer to keep the one I already got.  They do have an ad a S369 option but it's about $1000 more than the CC kit.  The Pusher kit relocates the battery and the auto trans heat exchanger I believe.  

 

I emailed Carls, Carl and his wife Diana both replied to me suggesting I go with the 1.15 housing for better spooling with my GXE.   I'm gonna sit on it over the weekend and do some more googling, but so far haven't found anyone who was disappointed with the CC kit.  

Well I went ahead and pulled the trigger.  The new turbo already arrived, just got to wait for the kit to get powder coated.  This turbo is huge, it's kind of intimidating.  

 

I got the rest of the kit last week, probably won't get around to installing it until my week off in August.  One thing I was curious about though is boost regulation.  Will I be able to set max boost through the wastegate on the smaller turbo as the larger one has no wastegate?

@Sycostang67I just wanted to say, NICE truck...love the color, it looks bad to the bone!

3 hours ago, W-T said:

@Sycostang67I just wanted to say, NICE truck...love the color, it looks bad to the bone!

Copper prices are going up, now I see why  

@Sycostang67 your going to need a bit of tweaking on that tune mostly the Low PSI Timing Reduct and the Timing Reduct Scaling... If is laggy on the turbos then go higher in both. If it lighting quick but staying retarded to long the short both up.