I guess it really depends on what your final speed goal is. Ideally you would want to build a powerband around shifting ~8k rpm and pushing it out in the final gear to the high speed you want. Luckily there are a lot of gearing options available.

Granted, if the question was 40-140, the better gearing would be stock final drive with Evo 8 3rd, 4th and pushing 4th out. This all depends if the pistons and block can withstand the 100mm crank throwing that piston against the cylinder at 8700rpm.

If the question was 40-170, then again, the preferred final drive may change again.

The only reason I see for a lower final drive ratio than stock is if you want to trap >140 in the 1/4 mile or if you are building your transmission around convenient places to shift on a track. Or... doing 40-150 pulls on the highway.

 

It works for me now and has for 15k. Since the question was 150 it necessitates using 5th as its on a 2.4. VIII 4th gear for sure for that application, I agree. I have driven the "autobahn" a few times and running a 4.0 FD with 2 gear changes is the answer, 3 gear changes sucks.

Here is my current gearing with a 245/45 (I use a 275/40 but its the same height)-



Notice if I start at 40 now in 3rd with a IX 3rd gear, I'm at 3400. Too work right I really need 2nd and start at 4500 (I can make 25psi or so at 4500) or start higher than 40. So I go 2-3-4-5 for 150. 4-5 is problematic at high rpm with a single synchro.

Here is the same gearing with a 4.0 (I would go back to a VIII 1st gear to make it work right on the street)-



2nd is now 3900 or so which is 21psi and a little easier to modulate on initial shock to traction, push to 3rd, hammer back 4th and I can pull 160.

 

I lost a HG but it could of been due to the car overheating for a minute. I had a power enterprises HG. Now using a AMS modified OE head gasket.