Nothing to dislike yet; have not attempted install as of yet. Liked that it came with up pipe. I thought it had an EWG fitting, but ended up being just an O2 sensor bung. 2 versions of qual length from Tomei apparently; can't find difference between the two. Did think it would be 4 to 1 design, but it's 4 to 2 to 1. Online descriptions not very good. Experience with IIR: only 1 to have IN STOCK, good price.I did not try emailing them with a question I had; which was recommended by the website, but they have yet to return my phone call & it's been over a week. Shipped in reasonable time. Experience with shipper: FedEx had it "out 4 delivery" 3 days in a row with out actually delivering & no updates came after signing up for such. Had to wait till 9 p.m. and check through original "shipped" email to find out. After calling customer service 3rd night, assured by human( in another country?) would be delivered the next day & it was. 2nd time very recently had this kind of problem with FedEx, not with USPS, UPS, or Amazon ( but their drivers have peeked into my cardboard box).