I had no issues at all, but I had a buddies shop install them. I've never installed DPs and don't have the time or desire to go through it. Did you follow a DIY guide?
The idle is a bit more pronounced when I initially start the car, but it settles down after about 20/30 seconds.
If you're sure it's the DP then reach out to tiago.
Hope you get it squared away soon. I LOVE my vrsf downpipes
Jet black e92 6mt 335xi:
18" BBS RGRs, KW v1, ESS Stage 2 flash, VRSF 7" FMIC, VRSF downpipes, JG Mods m-tech front, mtec V3 AEs, BMS OCC, hardwired valentine 1, p3cars gauge, amber delete, sport seats, factory oil cooler.