Just keep the AUW to 10.5 lbs or less and you will be happy. The engine is light enough to do this, although with the Focus attention must be paid at every step to use lighter weight components than the stock stuff supplied with the model.

Early in the thread there are quite a few posts detailing the mods I did to my Focus to incorporate the soft mount and the ES pipe. Biggest thing is you have to scrap the stock FG pipe tunnel and make a bigger and lighter one with balsa sheeting. This is on page 12, if I recall correctly.

Also, [link=http://www.rcuniverse.com/forum/fb.asp?m=9794144]Post #1071[/link] contains a very detailed "cookbook" of items needed - complete with links - in order to get very good pattern performance with the SAP 180.