I had taken my brand new Liva (white) for a Paint Sealant & Underbody (with 5 year service & warranty) on the very next day after delivery (25th Sep 2012). My Experience with them so far:
About Sidhu:
* Very very friendly guy, willing to listen patiently to what exactly your requirements are & strive to ensure customer satisfaction.
* A juice / coffee seems to be almost guaranteed to TBHPians at least (as far as I have seen in my couple of visits now; nice gesture.
* Ensures that the best outcome happens (in all stages including pre-work, work & post-work).
* He tries to personally drive each car from the wash-area to their 1st floor where the Sealant job gets done. This must be to ensure no mis-handling is done during these short-transits. Nice gesture again!
* He has a blue Nissan Sunny and a grayish Fluidic Verna. He proudly claims to have sticker-ed TBHPs on them even before getting his official number-plates done. He truly loves this Forum.
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He is awaiting for his wife's delivery shortly. Wish him and his wife lots of prayers and good luck!! About the work:
* I took a package of Paint Sealant + Underbody coating with 5 years warranty. Costed me a total of 6955 INR.
* I had a couple of yellow dots (result of our Pooja the previous night during car delivery). Turmeric stains were difficult to be removed, Siddu's team did their best to get it removed.
* Since mine was a new car, couldn't actually make out a huge difference on the paint Sealant coating. I am sure the results would be much better for a comparatively used car.
* Under-body coating was neatly done. They insisted me to take a look at it once completed - Good job guys!
* They give enough tips and tricks to the owners (like usage of dusters, wash frequency, micro-fiber cloth advantages, etc...). This has a dual advantage: 1. Car is maintained well to the max and 2. When the car is taken back to them for a regular maintenance, their work is reasonably reduced too

* Sure-shot to meet some fellow BHPians there - it is an "untold hotspot".
A short comparison:
There are guys who regularly leave their cars for a wash every fortnight (440 per wash = 880 per month). Worth I guess, as my car-wash chap takes 700 per month for a daily maintenance (wipe / dust - depending on rains) + weekend shampoo wash + waxing. When I compare both these expenses, 3M - though some 200 extra - is definitely a better take as it is done professionally. This might suit for those cars that are parked fully under cover (unlike mine that is parked on street). I plan to bring my Liva to them once in 2 months at least.
Sorry, no pictures taken during this job. Will be visiting them again in the next weeks for some exterior maintenance & shall take some pictures then.
Overall inference:
Good place for maintaining your car, these guys are knowledgeable and understand what you want. They can definitely keep your miles more clean and shiny --> 3M fixed prices might sound slightly pricey though (especially with no discounts being offered).
Cheers!!
M