I appreciate the well wishes reynoldston. I don't mind a little creative engineering but do hate spending money! I'm no mechanic but I manage to get by and I work cheap too. I can trace down wiring and drill new mounting holes if needed and even modify that muffler if I have to. Yeah, I guess I'll go for a swap and wade through the problems as they surface. Call me too dumb to give up and you'd be about right.
One thing I'd still love opinions on is whether there is a benefit in the extra cost for the Commercial Briggs over the Professional one. Looks like the commercial has an oil cooler and that sounds good, but are there other benefits or drawbacks?
Thanks again for everyone's suggestions
The commercial and professional are just new fancy names for the Intek and Vanguard. Briggs is changing the series names again for 2016 so Here we go again trying to figure out what engine is what. The engine with the oil cooler may also come with a 3 year warranty as opposed to the standard 2 year warranty. So also check what the warranty period is for the different engines.
If your mower has the exhaust manifold that slides into the muffler as opposed to welded as part of the muffler. You can sometimes find the same model of mower that has a briggs versus a Kohler, and then order the exhaust manifolds for that engine, and convert the exhaust. For example Cub Cadet may have had similar Z turns mowers with different engines for what that year.