Im gonna say the turbo seals are gone or you need a smaller restrictor. But hell ive ran my turbos without restrictors and just -3an feed lines with no smoking. Im gonna say seals man. If meets the criteria. Smoking as the rpms come down. Seals almost 100% If it wasnt doing it before the turbo install and its doing it now its more than likely it.
Your lines and everything look fine. You could try using the smaller restrictor but it probably wont solve the problem fully. Id just rebuild the turbo. If you have some decent skills you can rebuild it yourself using a Kamak kit found on Ebay. I have rebuilt 3 turbos, 2 t2's and one t3 and all came out great and didnt have any issues at all. If not send it off to get rebuilt or look for a new turbo in known good condition. T25's are a dime a dozen now a days. BTW you can use a rwd t25 as well, just swap the compressor housing to yours. Thats an easy one to do. One snap ring and bam. Just make sure you clock it the right way. hit up Zilvia.net and you can find t25's all over the place for $100 or so sometimes less. I got one that was freshly rebuilt for $100 shipped and its currently still being used on a car.