Question about parts for a RIA Tactical II

[XIIIthguards]

So I recently picked up a Rock Island Armory Tactical II, and I couldn't be happier with it in terms of performance. That being said, there were a couple mods I wanted to make to it, namely, replace the ambidextrous thumb safety with a non ambidextrous one and replace the slide stop with an extended version.
While they claim to be in name, I know that not all parts are universal when it comes to 1911's. My question is, what part brands should I be looking at to ensure that they will fit and operate correctly on my 1911, and what names should I look at for the best balance in terms of value and quality? This is the second RIA 1911 that I own, but I keep my GI model completely stock.

 

[Auto5]

The previous owner of my RIA Tactical replaced the ambi safety to accomodate the Magwell grips he installed. Unfortunately I cannot determine the manufacturer by examining it, but I imagine that only minor fitting, if any, would be needed.

 

[Technosavant]

RIA are pretty much box-stock 1911. Not even Series 80 firing pin block (where those parts are involved).

Thumb safeties do tend to take some fitting... the last thing you want is one that won't disengage or won't engage. Slide stop should drop right in though. 1911s often fall victim to the following "translations" of installation ease:

"Drop in" = Some minor fitting needed.
"Some fitting needed" = Take it to a gunsmith.
"Gunsmith installation recommended" = Take it to a gunsmith, bring lots of money.



As for brands of parts, I'd probably go with any decent name- Ed Brown, Wilson Combat, STI, Cylinder & Slide, that sort of thing.

 

[XIIIthguards]

I was kind of looking at the Wilson Combat, I know that is the brand that many people turn to, but the price is a bit of a turn off for me- $80 for a thumb safety just seems really high to me, even if it is a quality piece. May just have to suck it up- at least their pin sets can be had on eBay for about $12.