It really doesn't matter if you are modding a Sport, a Rubi, or an Unlimited......you are still basically talking about the same engine and tranny with new 35" tires. Steering, braking, and acceleration is all pretty much going to be the same, regardless of which model you are changing.
That being said, I would not recommend 4.10 gears for 35" tires with a manual tranny. If your buddy is running 3.73 gears w/ 33" tires ( I would not recommend that either) and you like it, then you'll probably like 35" tires on 4.10 gears. Myself, I would not be happy with it. I have 35" tires with 4.56 gears and there are many times I wish I had 4.88 gears.
I run a modified braking system (hydroboost) on my '98 and I would not go back to a stock setup.
As for steering....pushing new 35" rubber on the trails can be hard on stock components and an upgrade in this area would be welcomed as well.
There are plenty of modified 35" tired rigs on the road with less than desirable gear ratios, braking systems, and steering. And lots of their owners will tell you that they get along just fine....and they probably do. I prefer something more than just getting along.....and it took me a number of years to get it all put together.
What you want is up to you.....your $$, your rig, your decision.
One of my friend's that runs Moab with us each spring has an old YJ.....with a little 4 cylinder in it. Last time I checked, the engine had over 250K on it....never had the engine apart. He did some tranny work a couple of years ago. So yes, with good maintenance, it is certainly possible to see 200K miles on a SWB Jeep.