Hey mate,
yeah i would go a 4k or possibly 5k as they are still a straight swap, ive got a 4k in my rally car thats done 280,xxx km's and still has 155psi in all 4 cylinders with extractors through to a 2" exhaust, and i had a 32/36 weber on it. And it keeps up with skylines at my local car club and has no trouble sliding on dry bitumen. with the help of a locker of course. So if its just your daily keep a warm k series engine in it as they still do go very hard. But if you have the money ($5,000-$10,000)for the sr20de+t go for it.
i have a video of my 4k on bitumen but its VERY shit quality but ill chuck it up anyway.