Aluminum driveshaft, one of the first things i done to the coupe.
Welds/skinnies shortly after.
I was happy with the d/s, and the weld wheel is much noticeably lighter than something such as a pony rim, or even the alloy american racing rims i used to have. I dont like the skinnies, cuz you can kiss good braking and handling goodbye, although I drove my car everyday for 3 yrs with skinnies, still has them.
Btw, 6 yrs ago i paid 159$ for my driveshaft, I believe they are close to 300$ now
I bought my welds two at a time, then bought the skinnies when my funds allowed, cuz I could'nt go spend 1k all at once, also have to buy the lugnuts of course.
To answer your question, In my opinion, you'll be at least 2 tenths faster, but the shine on those welds, especially prostars makes it worth it. good luck.