If they've got the guides then you should be good to go. There's nothing particularly difficult in the fitting, just regular access hassle to the crankshaft pulley and alternator removal. Make sure you don't overtighten the belt; same procedure as the cambelt, a 90 degree twist on the longest belt run. If everything looks and sounds OK, you've now got to check the clearance between the belt and the ARB support bracket;this can be fag paper tight. If so I'd recommend you mark up where the belt passes the bracket and then remove the bracket and get grinding. A bit of an arse, but worth it. Enjoy your toothies but watch the rev limiter, you'll be hitting it in fourth now and it's pretty harsh.