In short:

I'm planing on spending around $2k on a TBE and a Unichip + tune by Tim Slako on MY00. Want just a slight performance upgrade but more concerned with longetivity of the setup plus my cold starts/air cons etc. Basically otherwise a factory standard car...no rough idle etc.

Anyone's done the same? Or can you see any problems in the setup? Any comments would be greatly appriciated.

Cold start and air-con will be same as standard, because Unichip is an interceptor, not a replacement ECU.

Your engine life will remain the same, if its tuned properly, and from experience, Tim's tunes are normally very safe, so you wont have a problem.

thanks for your opinion, would you invest in a knock link or similar? or once tuned and left alone it should be sweet?

The proposal is fine, much as was done by Tim Slako on my 99. and I agree with Balistc‘s comments.

Before going ahead: Check the Unichip comes with the boost controller, the early ones did not. And decide if you want to tune for 98 or 95 octane fuel.
Tim may use a knock detector when tuning but after that I doubt you would get any benefit from it.
Once done a Unichip tune lasts forever as long as you do no more mods, just replace plugs and check AFM every year or so. If you change the intake, use different fuel, put on another turbo, etc then you need to retune.

(With 98 you are limited to BP tho’ Caltex say on their site that Vortex 98 is to be in WA “from January” )

You wont need a knock link, but gauges never hurt.