I can't fault any of the TEC stuff I've bought. Rear shocks on my Bonneville are a massive improvement over OEM. A 2 into 2 exhaust was a good buy, lighter and better sound. I've had a luggage rack which was good quality too.
I stuck a set of Tec shocks on my old XBR500 a while back. They were shite but just about fit for purpose when I fitted them and absolutely useless after six of months use. Any kind of damping disappeared fairly early on, closely followed by the chrome and black paint.
I've just fitted the TEC fork upgrade springs and adjusters and rear gas shocks I also put Conti attack 3 tyres on my Street Twin and the handling is vastly improved. No complaints about TEC stuff, very reasonably priced and does the job. Time will tell although I'm sure they will help if there are any problems.
I have Hagon 2810's on mine and have transformed handing especially mid corner holds its line and doesn't pogo stick on undulations in the road.
I haven’t got around to doing anything to the suspension on the T100 yet. However it’s a very similar bike, in a lot of ways to my early 90s Sportster which was a right old donkey to ride when I first had it. Hagon rear units and Hagon single rate fork springs made a big difference. I then lashed out on Rico Intiminators (cartridge emulators) which between them, have really tamed it. Avon Cobra tyres also suited it very well. If was going to improve the suspension on the T100, which I rather doubt st this stage, that’s probably the route I would follow.