If you're just looking for some mild power (250hp), you will be happy with the T25 equipped DET. I recommend going with the F-MAX kit though, on your stock 95 motor. You will have ALOT of room for improvement in the future when you are ready to upgrade it. The stage I kit uses 370cc injectors and your stock MAF. These limit you to the 250hp mark, and you would probably run a t3/t04e with a .63 housing, which with the BB center section would be really quick to spool.
Later, when you are ready to sink more money in it, you can upgrade your fuel pump, MAF (to a Cobra MAF), and switch out to the 50 lb or 72 lb injectors. With this combo you should be able to hit about 350hp with the .63 exhaust housing turbo, or 400hp with the .82 exhaust housing. The stock ignition is good for about 350-360hp as long as you're not runnin H20 ignition. The water injection requires some more spark, but will allow you to run up to 14-15 psi on the street with this big turbo, on 91 octane gas and your stock 9.5:1 pistons.
There is tons of information about this on the SE-R.net mailing list archives, DET vs. F-MAX or what not. In the end, you may spend slightly more on the F-MAX kit, but IMHO will be rewarded with the ability to later run insane boost levels. Also, using the t3/t4 will make your motor a happier one, avoiding all the backpressure caused by the tiny t25
You will also have the advantage of running an external wastegate, which are super responsive.
Oh, and whoever said you have to upgade your cooling system, thats probably not true unless you live in hell (TX) or you do alot of road racing. Even then, i think the H20 ignition will do just fine keeping the combustion temps down. I'm running the stock cooling system and stock radiator with no problems in 109 degree summer temperature with the AC blasting. The NX2K brakes hold up just fine to my daily driving as well, since I don't drive like a maniac most of the time, but my tranny has been upgraded with a new input shaft, new 3rd gear all cryoed and mil spec shotpeened.
Turbo timer and boost controller are not needed for either kit, but are nice things to have. Bushings are also an option, though a good clutch will be needed for either turbo routes. I am pleased with the ACT 6 puck/HD PP i am using. People on the list complain its to harsh, but once you learn how to drive with it, you hardly notice its there.
Frank Orozco
96 200sx SE-R
F-MAX Stage II sleeper
350hp/320 ft lbs @ 22psi (c16 race fuel)
stock ignition, 15" stock wheels