The TQ converter is critical custom is the only way to go it really needs to match the combo. It really depends how much you want to spend, they vary greatly depending on the options you get. Since you have a turbo it needs to hold big power and be durable, I assume it is still a street car so most likely youll be under 3800rpm stall, with 9"-10".
Do you have dyno sheets so you can provide the details to the companies? That is best way so they can tailor the converter around where you make power and tq, you can never provide enough info. Here's a link to Lenny's build sheet
Ultimate Converter - Detail Spec
Lenny at UCC is the best around in my opinion ultimateconverter.com, then you can check out edgeracingconverters.com Andre is a good guy that stands behind his products. I have some buddies that have bought some stuff from redneck tranmissons (you can laugh it's alright) they have a store on ebay and get good remarks.