Honestly I don't see any point in going remote mount if you have the ROOM to do a front mount. It's a LOT of extra piping, your turbo/piping is exposed under the vehicle, and you have to worry about designing the oil feed/return.

^ agree if there's room up front, mount up front.

With room I'd probably say mount up front as well. I am a little bias toward rear mounts tho having done it myself.

Rear mount will give you lower engine bay temps and cooler intake air temps. Lag is not an issue provided you pick a smaller turbine A/R and you keep the exhaust temp as high as possible when it reaches the turbo. When the turbo is cool boost sucks but once the turbo/exhaust warms up there is not much difference with front or rear mount. Just have to design it properly.

Oil system was pretty simple and has worked perfectly. Many turbo vehicles use scavenge oil pumps where the turbo is mounted fairly low, the Porsche 911 turbo for example, only difference is the oil lines are a little longer. Make clean runs and keep the lines tied up neatly and you'll have no problems.

Even with the long compressor plumbing and oil lines I believe my install was easier than many front mount installs I've seen. Either front or rear mount can be great or crap, it all depends on the install and if you do your homework when designing it. I covered many of the details in my build thread, check it out.

That's my thoughts exactly. More material, but easier to do.

I certainly have a bunch more questions, but first would like to go through your write up (your Q45 is probably as close as it gets to my Pacifica 4.0; I consider installing 2 small KKK K26 or K27 making use of the dual exhaust setup my 'signature' series car currently has; hoping for low rpm torque from the quick spoolup small turbos).

Could you send the link to you build thread?

"I covered many of the details in my build thread, check it out. "

rear sleeper haha

I agree, I want to do a setup!!

One thing is the fact that you must have an oil accumulator mounted to drain the oil into a air free sump that feeds a special oil pump that will return the oil to the engine oil pan. Turbo piping from the rear of the car will entail the proper turbo a/r selection and piping choices to ensure a velocity that will provide good throttle response and charge air to the engine. The only advantage I can see is that you almost have to buy a "kit" that has the bugs worked out of it. Underhood installation will provide you with less
piping choice selection miscalculations and in my opinion more help form knowledgeable
people from support forums to help you out. Good luck!

I did a remote mount turbo in a 91 S10.
The turbo is mounted in the bed. The oil return setup consist of a 1/2 drain hose down to Tilton oil pump. The pump used in circle track cars to pump oil from the rear end to a cooler and back. So its made for hot oil. From the pump a 3/8 line runs along the frame and to the front and up to the valve cover. This has worked with no issues for 2 summers.

As for spool up weather it is front or remote mount I think it comes down to converter stall speed, exhaust A/R , timing , and fuel ratio.
If the converter is loose the other 3 dont effect it as much. If the converter is tight the motor will need lots of timing and a lean to slight enrichment to come up as fast as possible.

I started with a loose converter on this combo that would flash 3000 on a stockish 4.3 v6. Boost was instant. Seriously just short of N/A motor reaction. I swapped the converter for a different one that is much tighter and it has slowed spool time a bit.
Works kind good though cuz on street tires you can stab it from a stop and roll out and then it freeks out with power .

I made one for my 1990 miata. made a video on youtube. was really an inexepensive build. I was so impressed with its' ability to perform, even with such a crappy build that i am currently attending welding school with the desire to make kits for this type of layout.
lag is minimal to nonexistant. anything over 6psi and you will need an intercooler.
the only thing you really need welded is a flange for the turbo to the exhaust pipe.
oil pump was a turbowerx scavenge pump built for remotes. $299.
the trick is the turbo. getting the right sized hot side, coupled with a large enough compressor to feed the motor properly.

the rest of it is how well you have built your car. Engine management is KEY! you have to be able to control timing and fuel. PERIOD. all the boost in the world won't help you if you don't tune for it.

others were correct, mount it well, tie up the oil lines, and enjoy a much less expensive layout. oh, and the concerns over water and rain... utter hogwash. there have been low mounted turbos for DECADES... and it hasn't bothered them at all, and rear mounts are placed higher. lowest turbo i ever saw was slung on a 911. no one complained then...

pics and dyno from mine
https://www.homemadeturbo.com/attach...ine=1334313642
https://www.homemadeturbo.com/attach...ine=1334313642
https://www.homemadeturbo.com/attach...ine=1334313642
https://www.homemadeturbo.com/attach...ine=1334313642