Not all the same at all. Different geometries for each one. Some can keep stock A-arms. Some require tubular ones. Some move wheels out, forward, back, etc. Some allow moving motor back towards center of car.
Do some research on all of the major companies' products: Steeda, QA1, Griggs, Maximum Motorsports, Dugan Racing, etc...
AJE, MM, Kenny Brown, and Griggs are the best.
AJE, is really the only affordable one of the bunch, and it allows you to use stock control arms and springs, if you purchase the spring perches.
Expect to drop a G to get the rest of them in the car and running.
The rest may get bent up during Daily Driving usage.
Definetely no matter what you do, avoid UPR, it will NOT put up with street use.
i normally would suggest AJE or PA. but i read on the corral where a guy had a prob with his and the folks at PA. long thread about it. dont have a link, but a search should find it.
also remember that the MM, Griggs, QA1, Kenny brown will all mess with your wheelbase some. sothat means your tires may rub the fender wells once installed.