Does the MD5 have all the same size gears, shafts, etc as the 2D? Is it weaker in any way to make room for the fifth gear? Anything else someone should know before dropping that sort of coin? thanks

Yes, the MD5 has the same size gears,shafts,ect as the 2D.
No, it is not made weaker by the addition of the fifth gear.
If anything it is made stronger due to the fifth gear is straddled by bearings on either side.
let me ask you what kind of car will this be & what purpose is this car intended for?
Thank you, for the question

Click to view attachmentThanks for the answer. Makes me feel better about my plans. This is for a street legal sand rail. 2 seater with a 2.5 subi. I just wanted 5th for the street. Thinking at 60 mph the rpm would go from 3400 to around 2700. Then there is always that time in Idaho when you keeping looking for 5th.

thanks!

Thats a cool rail and street legal.
We use the MD5 for our street legal Manx projects which uses the Subi 3.0.
Below is a picture of the MD5 gear stack.
Click to view attachment
see this link for the cars we use the MD5 in that are off-road & street legal
http://mendeolamotors.com/motors/
I have a line on a used MD5 give us a call if your interested.