I can give you some guidance since my IS is very similar to yours, and by the way I've said the same too! Defiantly wanna keep the car forever haha!
Anyway, heres a short list of upgrades I've performed in relation to what you wanna do:
- Headlights
- New Satin Black Housing Head lights
- 6000k HID Xenons Dipped
- 8000k HID Xenons Fogs
- Brakes
- Brembo Discs, pads & calipers all round in yellow
Now I will say the brakes do feel a lot better, though they are not entirely needed, they do look great! (May have change the color of them once I get new wheels)
Now similar to your car mines got a black paint job, black wheels & black windows, this is how I bought the car and to be honest I'm not so keen on the all round black, it can give some people the wrong impression. It all depends on the look you wanna go for. Now personally I'd say go for the tinted windows BUT (and this is your choice) I would say balance the car out with a new set of wheels (not black) or return your current Lexus ones to standard and/or a different color, for example:
I'm looking into some Gunmetal, White or Matt Bronze 18" Rota GTR's or Grid Drifts for my car as I feel this will balance the colors on my car out a little, they also look amazing! However this is all my preference and you could have a totally different outlook on what you wanna do!
Here's a few pictures:
Bit rainy today but took a quick snapshot of the new headlights I installed yesterday:
P.S If anyone can guess the red car to the right of the first picture I'll be impressed ;)