Alky would be my choice.
You would see more performance for your dollar when it is time to upgrade the turbo. If you car is stock now, typically it would be wise to upgrade the converter too suit whatever turbo you choose, in order to see the most performance gain.
Meaning it's very easy to be disappointed performance wise, by throwing a larger turbo on the car without a matching converter. Unless you go dual ball bearing that is.
I look at alky injection as a very nice upgrade bolt on, that will help you make a lot more power on straight pump gas. This goes for every street driven EFI forced induction application, not just Turbo Buicks. On a Turbo Buick, it can mean the difference between a 16-17psi of boost with 20* timing at WOT combo and 22-25psi with 23* of timing at WOT combo. Huge power difference with a typical turbo upgrade under those conditions.
Higher boost and more timing, when combined together with enough octane for zero detonation, will always make more power on these cars. It's finding that magic combination that brings a permanent smile to your face.
HTH
with out question. my famous line for him is, "the customer service is worth the price by itself. let alone the kit, its performance, or easy of installation"
You'll need it later anyway for a bigger turbo....... but for now.... it can really wake even a stock turbo car up if it is on pump gas.... make sure you get a new chip from TT to go with your new alky kit.....