Out of the box I would say the TS1 would be the cleanest due to the reed valve. A lot of people fit aftermarket reed valves to the Racetour and MB offer such a conversion on their website for an additional £189 which would make for a very expensive kit imho. I've been running a touring tune TS1 for a year and found it to be pretty clean even though I ran it without a filter.
id go TS1 for all round performance and there easily tweaked for a 25 hp motor, The RT kits are good and ive used one for a couple of yrs but do push a bit back through carb which in fairness the TS1 can do aswell. Ts1 has built in reed and RT does not which is extra cost but then you have to whey that up against a pipe to fit kit.