I used a Part Number TH01489 from RockAuto UK - This slipped straight in to the internal pipe diameter, the rolled rim makes a smooth entry no filing or fettling other than the hole to drill. Additionally the 5 minutes install time on the 99p spent on cheepo grey plastic pip-lagging at Screwfix further halved the already reduced warm up time.
Most good UK 2.8's get around 33/34 MPG, many don't get anywhere near a consistent 33MPG. I'm not sure if I ever expected the mod to improve on my average 33+MPG - but I am sure most people will benefit from the 20%[ish] drop in MPG we would expect from the first 15 minutes of cold running when the weather drops to ≡ ≈ 5°C. My brother used to have a brand new Ford Galaxy MPV on a 2.2 that at £32k+ used to get take around 30 minutes to even be able to use the demister, and if he parked up to long waiting for her indoors coming out of the bingo the engine cooled so much he had to turn the fan blower off or his pins froze.
I'm saw a much reduced warm-up time [about 4 mins] and a noticeably mitigated diesel running costs over the next 5 UK weather months when I did the two mods below. This will very particularly applies to me [and any] infrequent user who travels only 15 miles in one go twice each week.
I also went solar maintainer that year and found that 2 years it worked and one year [lifestyle] it didn't. I'm currently looking at chucking my cheepo Maplins 4W panel and buying a better 10W panel & charge controller. The Maplins panel was always going to be on the extreme edge of useless when I bought it and I knew it at the time. The panel I'm now looking at should make more than a 1/2 A [1W] in the worst of the winter which is double the IOD mA loss 'at rest' on my 05.