I currently have a mixed lift system. I have rubicon express 3.5" coils and front track bar and rear track bar bracket. Then I have currie front lower control arms and rear upper control arms. Please note rear track bar is stock and rear lower control arms and front upper are stock. I do have after market drive shafts as well.

Now the question. I'm wondering can I change my springs out to 4.5" lift springs or do I need to finish replacing the rest of my control arms and rear track bar first??

I have bilstien 5100 shocks which work for both sets of springs as well.

 

You'll probably want the front upper arms and rear lower to properly adjust castor and re center axle. You might need to address Bumpstops, stabilizer links, and brake lines along with getting an adjustable rear trackbar

Sent from my SGH-I337M

 

The only thing I would add is that mixing a lift kit brand with a different control arm manufacturer is quite common and IMO acceptable, but I would stay away from introducing another brand for the new springs (Frankenlift). It makes it difficult to troubleshoot any problems you may have in the future or get manufacturer support.