If you have an upgraded alternator you'll barely notice the fan turning on. There is a very slight stumble as it kicks in. If you're not paying attention you might not notice it.
As for the controller it depends on what you want it to do and how much you want to pay. Most of us don't care about the hi-speed so we don't use that circuit. The lo-speed circuit doesn't draw as much power and can be run on a 40a relay. Although I'd probably get 60-80a relay if you can find one cheap. I've seen some for under $10. The 40a's are more like $5. It really doesn't matter that much though. I also highly recommend you using a circuit breaker (CB) instead of a standard blade fuse. You can get a 40a CB with 10-32 Threaded Studs for $4. Then all you need is a thermo switch. The Hayden 3653 Economy Adjustable Thermostatic Fan Control is around $16.
There's also the Hayden 3647 and the 3651 Adjustable Thermostatic Fan Control but I'm not sure of the quality. I had issues with my fuse holder melting because of the amp draw on a few occasions so I'm a bit skeptical that it won't still happen. There's no mention of the relay spec. I'm gonna guess it's the common 30a which is probably a little low even for the lo-speed. You'd then have to upgrade it to a 40a, in which case you'd be better off making your own harness/controller. I run 16awg for the dash switch and thermo and 14 awg for the power and fan. If you want to be color coordinated you'll need two spools of each. Otherwise you could just get one of each.
