If by "brought" you really meant "bought" then congrats. You have two underrated games. If you don't have them yet, get them both. Of the four titles you mentioned, three are must-haves for any rally fan: SLRE, DR and WRC 6.
I won't get into the specifics of each game since that has been done in other threads in this forum as well as the SLRE forum, not to mention discussions all over the 'net, but what I will say is that many people that bash SLRE and WRC 6 I think it's pretty apparent they haven't played the games. WRC 5 was utter garbage and SLRE has pretty poor graphics and sounds. It seems the badmouthing of those two issues were enough to generate a bad vibe regarding SLRE and WRC 6.
They're all rally games and each one has its pros and cons. Just a quick summary of the four, in order of preference (all IMO of course):
1. SLRE (Best physics of the current generation of rally games) MUST BUY
Pros: Physics; Car list; Stage Quantity and Quality; Can use rally, RX and PP cars on any track/stage you want
Cons: Graphics; Sounds; 30fps (though it runs near 60 on a high-end PC or PS4 Pro with Boost Mode)
2. DiRT Rally (Good physics - on the floaty side and too easy to throw the cars around) MUST BUY
Pros: Stage Quality; Co-Driver; Handling; 60fps
Cons: Floaty physics; Limited Content; Bare-Bones Presentation; No online rally
3. WRC 6 (Competent and intuitive simcade physics - fails at low speeds) BUY IF YOU NEED MORE RALLY
Pros: Official Cars (WRC, WRC2 and JWRC) and Rallies (13 of them); Super Special Stages; Tons of Content; eSports competitions
Cons: Cars lose torque at low speeds; screen tearing; 30fps (though it runs near 60 on PS4 Pro with Boost Mode); My goodness, that co-driver! A Fond!
4. DiRT 4 (Excellent underlying physics model totally ruined by releasing the game six months early - note I refer to rally mode and Sim handling; RallyX physics are great) DO NOT BUY (for now... must see if the many issues are ever addressed)
Pros: Rallycross physics; Procedural Stage Generator; Online Lobby options/features
Cons: Rally physics; Small car list; Very limited content (tracks and rallies); Procedural Stage Generator incredibly bland and repetitive; SHOULD BE IN ALPHA AT THIS STAGE; This game is not anywhere near finished.