1995 Accord

Hi! Currently I am driving a 95'Accord @ 108000. I have few concerns over some issues. The timing belt was not changed over 4 yrs. I decided to change it soon but is there any recommendations on which brand and type of timing belt should I changed into? Everytime I start my vehicle it would takes around 10mins to actually warm up (rpms goes below 1K), during the 10mins warm up the Rpm would idle between 1.5K-2.3K Whats is the problem with this? Anything I can do to it? I was looking into a set of new tires @ 14"rim size. Would it be recommended that I change a 15" tire to it? Any brands or types of tire is good for wet/dry weather? Lastly whenever I turn on the air-con heater to warm the air inside the car, there would be a stale smell coming from the air-con, but when I turn the temperature to much cooler, the stale smell will be gone. What is the problem with it? By the way, I happen to come across those addictive sold for booster performance and addicitve for cleaning the fuel injectors and etc. Is it really useful to use those addicitve for my 95"accord as its not a new posh car anymore, will it cause any damage to it instead? Any ways to boost the accerlation of the car as I notice when moving off time its kinda slow and it changes to 2nd gear around 3KRpm. Is this normal?

Thanks for your time and effort for my questions. Appreciate your useful solutions.