Reddit reviews Precision Instruments PREC2FR100F Wrench (3/8" Dr. Split Beam Torque w/Flex Head (20-100 Ft./Lbs))

No it won't affect it. If you're looking to get a nice one, I'd recommend the split beam style. They're accurate and quick to adjust settings on. The $50 ones with the dial on the end work okay until they don't and you crack off a bolt because they never click for you. This Brand was the manufacturer for SnapOn and other pro tool trucks for decades. I think it's the pricing sweet spot for buying once and done between the stuff you can't trust when you need to, like on an engine, and the stuff pros use now which are digital and $500.

Overpriced...

You can buy a USA made Snap-On quality (rebranded) split-beam torque wrench for a bit more. The Icon is Chinese junk marked up to USA made prices. There's no competition.

https://www.amazon.com/Precision-Instruments-PREC2FR100F-Wrench-Torque/dp/B000YOX568/ref=sr_1_3?ie=UTF8&qid=1526759120&sr=8-3&keywords=split+beam+torque+wrench+3%2F8&dpID=31vJarykCwL&preST=_SX300_QL70_&dpSrc=srch

I work as a mechanic for a large company that builds engines. All 99% of my work is engine or engine related.

1. Quality disassembly is as important as reassembly. It will literally decide how well things go for you when you go to put it back together. Take time to organize things in a way you will know how to put them back later. Buy some short multi colored zip ties and use those to remind you where hoses and wires go. Tie matching colors, one on each side as you disconnect and you wont be confused when you go to put the engine back in. At work I remove bolts and place them back into the holes they came out of best I can. Get a table or something you can lay everything out on. I lay things out left to right as I take them off, then I just go backwards as I put them back on.
   
   
2. Adopt the policy that anything worth doing is worth overdoing. By that I'm talking about thoroughness. I torque air boot clamps. It's over kill, but its right damnit.
   
   
3. Cleanliness is next to godliness when you tear open your engine, especially as it relates to any fuel systems or oil passages. Tape or plastics plugs can be used to cover them. When you're done working for the night, cover everything. Also, Lint free rags or towels are excellent especially when dealing with mains and rods. I put things on towels to keep them off dirty work tables.
   
   
4. As stated before, measure everything you can find specs for as you can. Quality straight edges, micormeters, feeler gauges, and even dial indicators can be bought for cheap. Especially compared to the price of having to do it over again.
   
   
5. I take everything apart with air tools, and reassemble most everything with torque wrenches. The danger for that for you would be that you lose the muscle memory of how something came apart. I see the same engines day in and day out so I at least have an educated guess how something went.
   
   
6. You don't have to replace everything you take off, but you should inspect everything, and weigh the cost benefit. The more work it takes, and the worse the results if it fails, the more likely am to not only replace, but to spend the money to make sure I have a good one. Oil pumps are an absolute to me, but I'm probably going to reuse the plug wires.
   
   
7. Dont be afraid to ask questions. New guys who dont ask questions in my shop make dumb mistakes that everyone sees (and worse, hears). New guys that do ask questions dont make the same dumb mistakes.
   
   
8. Quality tools can be bought in a lot places. Invest in the right tools. I own snap on, harbor freight, and everything in between.
   
   This is what I use, because it's the same company that makes the snap on ones.